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Cylinder head choice

9K views 66 replies 14 participants last post by  80vette383 
#1 ·
How's it going? I'm new to the forum, looking for some advice on the engine in my 1980 Corvette. A quick background, I bought the car when I was 16, and have been resto-modding it for the past 13yrs. I've gone through the entire car at this point from chassis, to drivetrain, to body and interior.

It started like this:





And has become this:






Anyways, on to my question.

I'm considering do an upgrade to my top end and I'm looking for some advice from some of the more experienced engine guys on here.

First, is it worth doing? Since building my first engine 7 years ago when I was 22 I've second guessed my head choice after talking with some different people. I'm running Edelbrock E-tec 170's which I had bought as part of their "power package" so it came with a matched cam and rpm air gap intake. The motor is a full roller 383 stroker (all the details below).

I've been happy with it, it's great on the street and it's run a best of 12.044 @ 112 with a 1.6s 60'. This wasn't under the best conditions, track prep wasn't great, I'm pretty sure it has more in it.

Alas, with all the nay-sayers saying the 170's are too small for a 383 stroker, I've spent the last 7yrs wondering if I've left a lot of power on the table. I built the short block strong and the engine only has 11k miles on it, so it should easily take more power. What I'm wondering is if it would be that much of a difference to make it worth doing... I'm leaning towards it probably is, I know there's WAY better head/cam combos out there, but I'm in no way an expert.

So, in addition to your thoughts on whether the Etec 170's are sufficient or I should go to something else, I'd also like to hear your recommendation on what heads I should look at.

As a side note, the current setup has developed some little external coolant leaks from the head gaskets and intake gasket... so it gives me a decent reason to justify a head swap to myself :mwink:

I know head choice depends on a lot, so if you need more info than what's below just ask, I definitely have it.

Thanks for any help!

Specs:

11.0:1 CR

-Bare 1987 hydraulic roller 350 block-Eagle Crank
-6" Forged Eagle Rods -Forged Mahle flat tops
-Aluminum Edelbrock E-tec 170s, 64cc chambers, 1.94" int/1.55" exh valves.
-Edelbrock Roller cam .539/.548
-Crane Cam Gold Race Extruded 1.5 rocker arms
-Comp Cams high energy hyrdaulic roller lifters
-Edelbrock RPM Air Gap intake
-Edelbrock Thunder Series AVS 650cfm
-XSPower Side pipes

-Built 700r4
-Rearend setup out of a '78 with Richmond 3.90 gears.
 
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#2 · (Edited)
The flow on those heads (if i saw the numbers right online) are pretty good. I get close to 500HP. For a street/strip car i'd stay with your set up on the motor or 'me personally i'd be content.' Are there heads for an SBC out there that will give you more than what you have,--yes. Your cam lift seems to be right. I mean if i had to just point out something-I'd rather have a 2.02/1.60 set up and perhaps a larger carb. Are you wanting more than what you have?:D
 
#5 ·
Thanks :thumbup:

We always want more! haha But I am pretty happy, I just was more wanting to make sure I wasnt significantly restricting my potential. I'm not too concerned with picking up more top end as it's only an occasional strip car. I had built it with the intention of having a lot of low-mid range power.

Where the gaskets are getting a little leaky and I may be pulling the heads to seal everything back up, I was thinking now would be the time to change heads if need be. But from the sounds of it, it may not be necessary? Maybe have some work done to these heads? Right now they're as cast out of the box.
 
#3 ·
How's it going? I'm new to the forum, looking for some advice on the engine in my 1980 Corvette. A quick background, I bought the car when I was 16, and have been resto-modding it for the past 13yrs. I've gone through the entire car at this point from chassis, to drivetrain, to body and interior.

It started like this:





And has become this:






Anyways, on to my question.

I'm considering do an upgrade to my top end and I'm looking for some advice from some of the more experienced engine guys on here.

First, is it worth doing? Since building my first engine 7 years ago when I was 22 I've second guessed my head choice after talking with some different people. I'm running Edelbrock E-tec 170's which I had bought as part of their "power package" so it came with a matched cam and rpm air gap intake. The motor is a full roller 383 stroker (all the details below).

I've been happy with it, it's great on the street and it's run a best of 12.044 @ 112 with a 1.6s 60'. This wasn't under the best conditions, track prep wasn't great, I'm pretty sure it has more in it.

Alas, with all the nay-sayers saying the 170's are too small for a 383 stroker, I've spent the last 7yrs wondering if I've left a lot of power on the table. I built the short block strong and the engine only has 11k miles on it, so it should easily take more power. What I'm wondering is if it would be that much of a difference to make it worth doing... I'm leaning towards it probably is, I know there's WAY better head/cam combos out there, but I'm in no way an expert.

So, in addition to your thoughts on whether the Etec 170's are sufficient or I should go to something else, I'd also like to hear your recommendation on what heads I should look at.

As a side note, the current setup has developed some little external coolant leaks from the head gaskets and intake gasket... so it gives me a decent reason to justify a head swap to myself :mwink:

I know head choice depends on a lot, so if you need more info than what's below just ask, I definitely have it.

Thanks for any help!

Specs:

11.0:1 CR

-Bare 1987 hydraulic roller 350 block-Eagle Crank
-6" Forged Eagle Rods -Forged Mahle flat tops
-Aluminum Edelbrock E-tec 170s, 64cc chambers, 1.94" int/1.55" exh valves.
-Edelbrock Roller cam .539/.548
-Crane Cam Gold Race Extruded 1.5 rocker arms
-Comp Cams high energy hyrdaulic roller lifters
-Edelbrock RPM Air Gap intake
-Edelbrock Thunder Series AVS 650cfm
-XSPower Side pipes

-Built 700r4
-Rearend setup out of a '78 with Richmond 3.90 gears.

That's a pretty good set up you've done, A set of heads like AFR 190s and 1.6 rockers would pick up the top end by 20-25 horsepower. From a 350 that's about the top without going into something that would be great at the track but miserable on the street. So that decision is up to you. That change would be not only heads but a lot more cam and carb; plus a lot of carving to get a bigger exhaust system in there.


Great looking ride.



Bogie
 
#4 ·
I looked up the flow numbers for the E-Tec 170's on Stan Weiss' Cylinder Head Database....the E-Tec 170's are a virtual clone of the flow numbers posted for stock Vortec heads.
_____Intake...........Exhaust @28" water.
.100" - 64...............54
.200" - 130.............104
.300" - 186.............140
.400" - 220.............169
.500" - 232.............183
.600" - 238.............190

So they're not terrible, but in the aftermarket arena there are certainly a good number of better choices.
If I had to guess right now I'd say your making about 420HP.

ProFiler 195's, combined with a 750 cfm carb will pick it up across the rpm range, and pick the peak up 60+HP
Even the 195cc Profilers would pick you up a good amount, but the 195's are better suited to the cubic inches you have.
AFR 195's would do the same.

Your carburetor is definitely too small.

I agree with Bogie, a 1.6 rocker on the intake side will help too.

Very sharp looking car you have there :thumbup:
 
#7 ·
Thanks for the info!

The carb was a point of contention. I had thought a 750 would be a good choice, but at the recommendation of my engine builder and Summit I went with the 650. Using a CFM calculator it did come out around 650, maybe a little more. I have considered going to a 750 Holley though.
 
#8 ·
If low speed drivability is of prime concern, then the carb CFM calculators work....but if power is more of a concern racers and street/strip guys have learned you need to ad at least 100cfm to what the calculator predicts.

that's why the 950 Holley is so popular on Hot Street/Strip and race 377-427" small blocks.

Going large on cfm is even more important on dual plane intakes because they effectively divide the carb in half, as each cylinder can only "see" half the carb barrels....even with a cut down plenum divider, which helps ....your 650 would be more ideal on a single plane intake.

A good 195 cc head would push you up near the 500HP mark with the bigger carb and rocker arms, and not really give up much down low at all. I'd bet you actually don't have a need for more low end power with the super low 3.06 1st gear in the 700R4 trans combined with the 3.90 gear....got to be a tire smoke fest now ;)
 
#10 ·
I agree that 195 AFRs would be your best bet. And maybe the Edelbrock carb isn't ideal, but not because of the 650 CFM rating. Even at 90% VE, a 383 can consume only 598 CFM at 6000 RPM. And if you go with a 750 that has larger primary bores than your current carb, you stand to lose some throttle response crispness. Unless you're at WOT all the time, it's all about velocity in the primaries, not volume.

Read the article below and pay special attention to what was gained when going from 650 to 750 carb. And of course, a dyno can't measure loss of throttle response.

Power Testing Seven Holley Carbs - Tech Article - Chevy High Performance Magazine
 
#11 · (Edited)
Do you have the LSA and duration at .050" lift numbers for that roller cam?

What's the rear tire size? Are the ones in the picture the same as used at the track? Your 1.6 sec. 60' sounds like some stickies tires?

Eric makes a good point, you're at about 12:1 overall gearing in 1st gear... Enough force at the tire contact point to lift about 2 Corvettes straight up... Add in 2x more from the torque converter for the first 20' and lift about 4 'Vettes straight up... (figuring an 11:1 compression ratio 383" at about 475 - 525 lb.-ft. of torque) .. Is that about the ridiculous amount of power you have in 1st gear? Seems like you could easily give up a tad of that for more top RPMs HP... What's your converter stall RPMs?

Since you need about 25-30cc's hogged out of each head port (8 x 30 = whopping 240ccs, more aluminum than would fill one intake port!) and might as well go bigger valves, I'd suggest selling the current heads and simply buying what you need... with only 11 K miles on them, can prolly get close to what they sell for new...

Here's a torque build up on a 383" engine with stock Vortec heads (except springs) (HP held down by head size):
GM HT383 Crate Small-Block - Engine Build - Hot Rod Network
Of course, your engine would prolly be even hotter with the same parts...
.
 
#12 ·
Do you have the LSA and duration at .050" lift numbers for that roller cam?
Edelbrock #2201 Rolling Thunder Hydraulic Roller
Advertised duration 296/300
0.050" duration 234/238
Hydraulic Intensity 62. This is the same H.I. that Harvey Crane used to cut all the cams he ground, so it may be a Crane lobe profile.
Valve lift 0.539"/0.548"
Intake centerline 107
Exhaust centerline 117
Lobe separation angle 112
Vacuum @1,000 rpm's, 12" of mercury
Operating range 1500-6500
Intake opens 10 degrees BTDC
Intake closes 44 degrees ABDC
Exhaust opens 56 degrees BBDC
Exhaust closes 2 degrees ATDC
Edelbrock recommends using their #7800 timing set.
 
#14 ·
First and foremost - nice job - that is a sharp Vette.

2nd -buy the best heads you can afford - AFR 1st and Profiler 2nd would be my choices.

3rd, since you've put the time, effort and love into this car I'd recommend a swap to a TB EFI. FITech if budget is a concern or Holley if budget is not a concern. If EFI is not in the plan, then the venerable 3310 Holley would suit your build and driving style the best IMHO.

Good luck and again, nice job young man!!!:thumbup:
 
#15 ·
QUOTE:
And maybe the Edelbrock carb isn't ideal, but not because of the 650 CFM rating. Even at 90% VE, a 383 can consume only 598 CFM at 6000 RPM. And if you go with a 750 that has larger primary bores than your current carb, you stand to lose some throttle response crispness. Unless you're at WOT all the time, it's all about velocity in the primaries, not volume.



Please ignore this post totally!

By his math you don't need bigger heads either as you are not using the full 232 cfm your heads flow.

You "DO" need a bigger carb.
I would use profiler 195 cc heads and an 850 cfm carb as a minimum.

Note my car in my icon? Same bolts you are working with. I bet just changing the carb and some serious tuning you should drop a couple 1/10s
 
#16 ·
QUOTE: "Even at 90% VE, a 383 can consume only 598 CFM at 6000 RPM."
_________________________________________________________

Please ignore this ... By his math you don't need bigger ... I bet just changing the carb and some serious tuning you should drop a couple 1/10s
Yeah, Vinnie, I was thinking the same thing when I saw that... wouldn't be surprised if this well designed engine did 101-102% VE !!!
 
#21 ·
The combination is pretty good as is. It could use some tweaks but based on the flow numbers the potential out of the mill is around 450HP. You can use the heads you have and have work done on them. A valve upgrade along with bowl work will raise them another 20 or so CFM and get you to the potential of a 500HP.
As stated you can put a set of AFR195's on the engine along with the correct cam and be over 500HP. I have attached a dyno sheet of a pump gas 383 with the AFR195's and a correct camshaft. A carb upgrade of an 850 would be best also.
 

Attachments

#22 ·
So, the decision has been made... somewhat.


I decided to pull the motor. After 7yrs it really needed to be gone through. It's still running really good, but something seemed to be going on with cyl #1 and #7, I think related to some leaky head gaskets.


Shortly after I first had it built the head gaskets started leaking externally, and over the past few years it started getting worse. I think coolant may have been getting into cyl 1 and 7, looking at the exhaust ports anyways. Cylinder 7 was definitely burning some oil too, but looking at the spark plug threads I think that may have been a valve cover gasket leaking down and in through the spark plug. Also, cylinder 3 and 5, and 4 and 6 look pretty lean (the exhaust ports are very white), I'm not sure if the fact that the last thing I ran was C4 has anything to do with the white look. Could the lead do that?


Here are some pics, how do you guys think each cylinder looks?

































I appreciate any input. From here I'm bringing it to a reputable engine builder to have it gone through and freshened up. As far as my decision on the heads, I'm going to talk to the guy at the engine shop. I think I'll either go with some AFRs like you guys recommended, or have him work the E-tec 170s I already have to get a little more out of them. That decision will be made once I see what's going on with the rest of the engine.
 
#24 ·
So, the decision has been made... somewhat.


I decided to pull the motor. After 7yrs it really needed to be gone through. It's still running really good, but something seemed to be going on with cyl #1 and #7, I think related to some leaky head gaskets.



I appreciate any input. From here I'm bringing it to a reputable engine builder to have it gone through and freshened up. As far as my decision on the heads, I'm going to talk to the guy at the engine shop. I think I'll either go with some AFRs like you guys recommended, or have him work the E-tec 170s I already have to get a little more out of them. That decision will be made once I see what's going on with the rest of the engine.
EXCELLENT decision to talk to the local guy. Reworking your current heads is a viable option if, repeat if, you have someone that has the necessary knowledge.

Are you going to tear it down or let the machine shop tear it down?
 
#25 ·
There is nothing wrong with the setup you have now but Edelbrock heads always need some work. Bigger valves, bowl blending, etc. I would probably purchase a set of 195cc ProFiler heads, Edelbrock Performer RPM, and a 950 Holley. Don't worry about it being too big, it is just a 750 main body on a 850 base plate. I don't care for the Air Gap manifold because it has problems when the weather gets cold. The ProFiler heads are American made and you can save a few hundred buck over AFR heads. If you want a new camshaft to go with the new heads check out this Howards Hyd. roller camshaft. https://www.summitracing.com/parts/hrs-110525-10/overview/ Don't forget to talk with Howard's valve springs to match the camshaft and here is a good set of Howards lifters. https://www.summitracing.com/parts/hrs-91164n/overview/make/chevrolet
 
#27 ·
So the machine shop called...... the news isn't good.

To be honest, I can't believe how well the motor was running with the problems found. Heres what they got:

-Broken main cap
-Block was never decked by the previous machine shop. It's an 87 350 block I had gotten, and it's never been decked. He said it desperately needs it, which is why the head gaskets were leaking so bad.
-Fuel pump rod wasn't right and wiped out the cam.

Everything else is in good shape

Heres what they want/need to do:

-Main cap needs to be replaced, block bored and line honed. It's a .030 over right now, he said theres some minor scratches but it should clean up nice at .040 max.
-New pistons to fit new bore
-Deck the block
-Mill the heads
-Replace the cam (this will give me the chance to go with a more aggressive custom cam) Suggestions?
-Plus all new hardware, better quality gaskets, performance cam and main bearings.

For the heads he did agree they are the limiting factor on the motor, but said he's had good success with at minimum porting the bowls which he said seems to be a sloppy spot on these heads. He said he could go further and port the runners and ports, but at that point I'd be better off buying new heads.

Also, I'm going to be pumping up to a Holley 750, he recommended the HP 750.

So, what are your thoughts? I know I could probably by another crate motor, but at least I know what I have and I know it's definitely done right. Some added bonuses, included in the price is engine dyno tuning and break in. After the break in they drain the oil and cut the filter and inspect everything! Sounds very thorough to me.

Any suggestions on cam? I was thinking about calling Lunati and/or Comp cams and seeing what they recommend.
 
#29 ·
Is that a broken 2-bolt main cap or 4-bolt main?? Lucky your inspection idea caught that before it made a real mess of things. :thumbup:

What main bearing position was it, 1,2,3, or 4??
If it is 2, 3, or 4 and a 2-bolt block, now is the ideal time to add splayed steel caps, as other than the cost of the caps the install won't cost you that much more than just replacing one cap with another stock cast cap, since almost all the same machine set-up still needs to be done...and that is where the largest portion of the expense is( the Time = Money deal).

If you are buying a new carb, on a dual plane intake the 750 is still too small....if on a single plane it will be all right.

As far as a cam, you would be a lot better off to call a real custom camshaft specialist like Straub Technologies, Mike Jones @ Jones Camshaft Designs, Rick Jones @ Dick Jones Camshaft Designs.
The bad thing about big companies like Lunati, Comp Cams and Crane Cams is if you make 1 call to each every day for 5 days you will end up with close to 4-5 different recommendations from each company, often even if you talk to the same Tech, leaving you with 20+ possible choices and still may not have one of those 20 that is the ideal choice.

If not going the full custom route IMO you'd be better off with a smaller company like Bullet Cams or Cam Motion. With a smaller customer base they are more interested in helping you.

I'm assuming you now know the hydro roller cam needs either a bronze tipped, a composite material, or a roller wheel tipped fuel pump pushrod.

Just the basic bowl work on the E-Tec 170's isn't going to get you much power gain, they really need the full port work over. You might be better off selling them off in good stock shape and buying a better head than spending a bunch on port work.

Your chosen shop sounds like a place that knows how to take care of their customers, so that is a plus.
 
#30 ·
Is that a broken 2-bolt main cap or 4-bolt main?? Lucky your inspection idea caught that before it made a real mess of things. :thumbup:
-Yeah, I was pretty surprised when he said it. The block is a 1987 4 bolt main 1pc RMS.

What main bearing position was it, 1,2,3, or 4??
If it is 2, 3, or 4 and a 2-bolt block, now is the ideal time to add splayed steel caps, as other than the cost of the caps the install won't cost you that much more than just replacing one cap with another stock cast cap, since almost all the same machine set-up still needs to be done...and that is where the largest portion of the expense is( the Time = Money deal).
-I'll find out when I call him back which one it was. I'm going to see if he can send me some pictures since they're 1.5hrs away from me.

If you are buying a new carb, on a dual plane intake the 750 is still too small....if on a single plane it will be all right.
I am running a dual plane, it's an Edelbrock RPM Air Gap. You think the 750 is too small? I'm afraid to go any bigger because it's mostly a street car, and from everything I've read I'll lose throttle response the bigger I go...? Also, I was looking at a 750 Ultra double pumper, but the engine builder recommended a 750 HP with no choke. I'm going to call Holley for their opinion, but what do you guys think?

As far as a cam, you would be a lot better off to call a real custom camshaft specialist like Straub Technologies, Mike Jones @ Jones Camshaft Designs, Rick Jones @ Dick Jones Camshaft Designs.
The bad thing about big companies like Lunati, Comp Cams and Crane Cams is if you make 1 call to each every day for 5 days you will end up with close to 4-5 different recommendations from each company, often even if you talk to the same Tech, leaving you with 20+ possible choices and still may not have one of those 20 that is the ideal choice.
That's a good point, I'll try calling them too. I called Comp and Lunati this morning. The guy at Comp was actually really good, he spent a lot of time working different combinations because he was worried about not making enough vacuum for the brakes. He wound up suggesting starting with one of their cams and doing a custom grind on it. The guy at Lunati was very quick and just recommended an off the shelf Voodoo cam with more lift and duration than the Comp cam guy recommended, and he didn't seem concerned about the brakes at all... he just said it would be "enough".


I'm assuming you now know the hydro roller cam needs either a bronze tipped, a composite material, or a roller wheel tipped fuel pump pushrod.
Yup, I do NOW! :spank::spank:

Just the basic bowl work on the E-Tec 170's isn't going to get you much power gain, they really need the full port work over. You might be better off selling them off in good stock shape and buying a better head than spending a bunch on port work.
Yeah, I'm in a tough spot. I've gotten a lot of recommendations on here and Corvetteforum to go to AFRs or Profiler heads. The thing is on top of the cost of heads I'll also need a non-Vortec style intake manifold, it just opens up another can of worms. If I do the runner and port work too that'll bump me up to about $850, versus $250 for just the bowl work. At $850 I'm that at the point where it would be more logical to get better heads, but then I'm probably up to about $1500-2000 just for heads and intake depending on which way I do. He seemed pretty sure that the bowls are a real weak spot on these heads and cleaning them up would at least help some, not a ton, but according to him probably enough to get me up to 450-460hp from the approx. 410-420 I'm at now (in combination with the new cam and carb of course, not just the porting).

Your chosen shop sounds like a place that knows how to take care of their customers, so that is a plus.
Yeah, I've been very happy so far and I'm just getting started. I'm going to be calling him back soon with the go ahead, just need to figure out a couple more things.
 
#31 · (Edited)
I agree COMPLETELY with Eric.

Also know, if running a manual gearbox; when you line bore the block after installing the new cap (Good idea by Eric to investigate splayed 4-bolt caps), you'll always need to use offset dowel pins to re-align the bellhousing with the crankshaft centerline.

Welcome to project creep; if you go with some killer heads, then the carb choice is again too small technically. If it was me; I would look at the ProFiler head offerings (or the ATK branded ones), and a QuickFuel or AED 850-ish Holley-type carb. For all out power, a 950 isn't unheard of.

Heads first, THEN cam. Often, a good cam company will want the ACTUAL flow numbers from the ACTUAL heads going on the car; not the mfg published numbers. Buy the bare castings, and have your shop assemble them with quality parts. Gasket matching doesn't do much, have him focus on the valvejob and a light clean up; with some attention paid to the exhaust side of things if anything.
 
#32 ·
I agree COMPLETELY with Eric.

Also know, if running a manual gearbox; when you line bore the block after installing the new cap (Good idea by Eric to investigate splayed 4-bolt caps), you'll always need to use offset dowel pins to re-align the bellhousing with the crankshaft centerline.

Welcome to project creep; if you go with some ****** heads, then the carb choice is again too small technically. If it was me; I would look at the ProFiler head offerings (or the ATK branded ones), and a QuickFuel or AED 850-ish Holley-type carb. For all out power, a 950 isn't unheard of.

Heads first, THEN cam. Often, a good cam company will want the ACTUAL flow numbers from the ACTUAL heads going on the car; not the mfg published numbers. Buy the bare castings, and have your shop assemble them with quality parts. Gasket matching doesn't do much, have him focus on the valvejob and a light clean up; with some attention paid to the exhaust side of things if anything.

Thanks! Also that is one thing I forgot, a valve job is on the list of what he's going to do, plus new valve springs.
 
#35 ·
I can understand your tie-up with a head change due to the Vortec bolt pattern intake.
Seems strange to me in this age that the majority of head manufacturers don't just automatically put both patterns on there....seems like a no-brainer to me at the manufacturing point.

The Holley Ultra HP and regular HP are at the basic level the same carb....the Ultra just has a bunch more adjustability and the fancy coatings.

I would say to stop worrying about low rpm torque....I've been there and you have reached the point that with 383 cubes and coordinated heads, compression and camshaft that the last thing you need is any increase in low end and can actually look to maintain the torque you have right now(and even give a bit away really) and push for mid to upper rpm gains....especially since you have sooo much gearing with the 3.06 low and 3.90 rear axle. Low gear and WOT has to be just about worthless on street rubber?!!

I'm interested to see how this dyno's out.
 
#36 ·
Thanks. Yeah I should clarify, I'm not really looking to necessarily increase torque down low, just maintain it. The car dynod somewhere around 420wtq on a land and sea chassis dyno shortly after this motor was first built. I'm pretty happy with that, I just don't want to lose any! Haha

So the double pumper and HP are basically the same? I know the ultra double has more features than the regular double pumper, but the HP is the same too?

I'll definitely keep you guys updated, and keep picking your brains along the way, so stay tuned.
 
#37 ·
80Vette:

Thanks for keeping us updated. It'll be good to have an 'end user' documented experience of the process, as far as getting the head work done; and how that relates to getting a custom cam profile, opposed to 'shelf stock'. Many of the guys on the web are industry guys, and it can be hard for a guy in your shoes. These details DO matter; but many of us are conditioned to pick parts out of a catalog and go for "its just a street car" and "its good enough".

I love your combo, and I generally don't like the late C3's; but yours is KILLER and kinda changing my opinion LOL

Thanks again for sharing all this!
 
#39 ·
The Ultra HP has the integrated idle air adjustable by-pass(Barry grant started this, called it Idle-EZ), so you don't have to crank up the idle speed screw to get enough air in at idle but mess up the throttle blade tip-to-transfer slot relationship
It has a billet baseplate and metering blocks instead of cast parts.
The metering blocks have every metering orifice removable for adjustability. Jetting, power valve restriction, idle feed restriction, emulsion well orifices

The regular HP is all cast parts, no idle air adjustment, and does not have fully adjustable metering blocks, just jetting.

Both have the same venture contour on the main body and no choke tower.

The Ultra HP has a whole bunch of minor improvements and easy of use refinements for racers also that the regular HP doesn't have.

If you are looking to spend for the Ultra HP, you are within about $100 of FITech Go EFI4 600HP version self learning throttle body injection that would bolt right to you intake manifold.... and since you are also looking to upgrade your fuel system too, they have an inline pump kit that you could easily just splice right into your factory 3/8" steel line and be set to go. You might want to take a real close look at that before shelling out for an Ultra HP and a bigger mechanical pump with larger fuel lines and larger pick-up in the tank.

The Fuel Injection because of it's high pressure works with the existing tank pick-up and line diameters.. FITech's pump speed control also means no return line is needed.
Hell of a deal to look at if you ask me. Almost $900 is ridiculous for something as simple as a carb and your cost on the carb doesn't include the cost of larger lines and larger tank pickup that drive the price right up to equal the fuel injection.
 
#40 ·
Thanks for the info!

To be honest, my biggest hold up on the FI is my side exhaust haha I don't want to have to put O2 sensors in my side headers, and I don't want to give up my side pipes. Maybe someday, but not yet.

As far as the Ultra double pumper Summit lists it at $582, and I'm able to get it through another vendor I have a discount with for $519. I think that's pretty reasonable, plus I'm hoping to get around $200 for my Edelbrock.
 
#41 ·
The O2 sensors could be put in facing inboard, parallel to the ground were they will be difficult to notice.

Just an idea, and they don't have to be level parallel, they can be tipped down or up as needed for clearance.

IMO $200 is generous for a used Elder-Broke, $75-125 is a more common price, they are listed a lot on Ebay and Craigslist.

As you can see, I'm not an "E-brock" fan....they're charging too much for middle of the road performance potential.
 
#42 ·
Yeah there's definitely guys doing it, but I'm not quite ready to go down that road. My fuel system would need some definite upgrading on top of the FI system. The nice thing is I can always add it later and sell the Holley off for a decent price. I think it'll be a good winter project in the next few years.

Yeah I think 200"ish" haha. I think I listed it for 175 to start. I know edelbrock is a mainstream big box brand, and I don't have a ton of comparisons to make (I've only ever had this edelbrock and a rochester q-jet), but I can't knock them too much. Their top end kit got me just about into the 11s on a motor I think may have been questionably built to begin with.
 
#43 ·
Just catching up on your progress - wow you've had a lot!

Most importantly IMO, great to hear you've found a reputable shop that sounds like they are on their 'A' game. You have to trust your machine shop when you're at the point you're presently at. Whether they currently have earned your trust sufficiently will be determined by the end result - it's a gamble that you have to take. I think it's the reason that so many people 'fall in love' with 'their machinist/shop' - because their guy is trustworthy. Hopefully you've found someone of that caliber that you can use for decades.

To recap what I've read, you are reusing the rods, crank, and the repaired block. You need to get new pistons and rings for the overbore, new cam bushings, a set of splayed caps, and a line bore. I haven't seen anyone else mention it, but I think you're getting pretty close in block repairs to the cost of an SHP block that will need a set of cam bushings, a light deck surface cleanup and a hone. And seeing you already need new pistons, then you could step up to a 4.125 bore and have a 400 that can be rebored safely .080 for many rebuilds to come.

I know the previous paragraph is how these repairs develop mushrooming costs, but I thought it was worth mentioning. And personally, I don't see anything wrong with what you're doing presently as long as you aren't going to develop a notion to put a 150-200 shot of laughing gas to it a couple of years from now :thumbup:

Other than the observation about the block expense, everyone else has you headed in the right direction IMO. I'll mention that I'm a happy/satisfied Straub customer - I'm not endorsing him as I'm not experienced with custom cam grinders, but I have nothing bad to say about his company in terms of product quality and customer service. Chris and his people are a great group that answer questions (and the phone) when asked.
 
#44 ·
Thanks for all the advice so far. FWIW, I talked to the machine shop today to get a little clarification on the main caps for my own understanding. I didn't ask which cylinder, but it's one of the 3 center main caps that let go, he thinks probably due to detonation. (That's the down side to straight through side pipes, hard to pick up pinging :smack:) Anyways, he said usually the problem is in the 3 center caps, and the front and rear caps rarely fail. The part that was clarified for me is they are not replacing ONLY the broken cap, they are going to fit 3 new (used) caps to the center mains.

I'm facing two other decisions right now.

First, I'm planning on going with Straub for the cam like you guys recommended. I talked to Chris and where the shop is going to do some port work he wants to wait until we get some flow numbers before spec'ing the cam. My decision I need to make is what to do with the lifters. I know whether or not to replace roller lifters when replacing a roller cam (or vice versa) depends on who you talk to. My engine builder said he planned on reusing the lifters as they look like they are in good shape. The engine only had 10k miles on it with about 30-35 1/4mi passes, so the lifters should be pretty new. The lifters were actually swapped out when the engine had 1k miles, due to a mistake by the original engine builder, so they have even less use on them. I know lifters aren't a ton more $$, but with the amount I'm unexpectedly putting into the engine all of the sudden, I'd like to save where and if I can. If it's something that's definitely necessary I have no problem doing it, but I'd hate to throw away perfectly good parts for no reason. Any advice?


The second decision should be a little easier! :smack: I need to settle on a carb. As I mentioned, the engine builder had suggested looking at the Holley HP 750. I had been looking at the Holley Ultra Double Pumper 750. I need to decide between the two of those, but more importantly I need to decide if I want to go with Vacuum or Mechanical secondaries. From everything I read my car could kind of go either way, it's an automatic, on the lighter side but not super light, and low rear gears. Any recommendations here? My main thing is I want to maintain good throttle response.
 
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#45 ·
So are you saying you would go with the mechanical or vacuum?

Yeah I'll have to think over the lifters, I guess for the money it wouldn't be bad to just take care of them now. Right now I have Comp roller lifters.

I'm in no rush, I think waiting for the flow numbers is a great idea. Seems more thorough to me, that was the main reason I decided to go with Straub.
 
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