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  #46 (permalink)  
Old 10-26-2012, 05:40 PM
How fast is fast enough?
 
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Originally Posted by 85jimmy350 View Post
I guess maybe a little more information about me and what I'm after might be helpful. First off I am a perfectionist and I have strong OCD tendencies. I'm not looking to take any short cuts and I don't do things with the "good enough" mindset. The budget is less of a budget and more of a personal challenge. I would imagine just about anyone can throw 10k at (insert parts store name) and make decent HP, but I want to challenge myself to learn how to do as much as I can and I intend to do everything myself with the exception of machine work on the block. If parts are reusable and adequate to get me in the HP range I'm shooting for I don't mind cleaning them up and reusing them but I'm not going to work my but off putting something together knowing that I'm reusing a part/parts that really shouldn't be used.



That is what I plan to do with the first of the two engines. It is a complete engine, the only thing it is missing is exhaust manifold. I plan to reuse as much as I can and return it to stock with the exception of a port and polish on the heads for practice before I move onto the second engine.

The second engine is the one I'm trying to make HP with and my goal with it is to get 350-400 HP. With trying to get that amount of HP out of 350 on a budget I assume it will force me to learn how to match the cam, pistons, heads, intake and carb. Right now if I get on a parts website and and start reading cam numbers or CFM numbers etc I look at it as bigger must mean better but bigger also means more expensive so I'm trying to learn how to maximize bang for the buck instead of just throw a bunch of dollars at it.
400hp can be done with a very streetable combo using mostly stock parts. You have to be sure to NOT go too big though.

Run a basic 350 with flat top pistons and some 64cc chevy heads with a good clean port job and 1.94/1.5 valves. A used RPM intake, a good carb (650cfm+), good HEI ignition, and a decent set of 1 5/8" headers, and a cam in the 220ish range and all the lift you can get.

There really is no reason you couldn't get it built for less than a grand if you find a good core.

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Old 10-26-2012, 10:14 PM
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Originally Posted by hcompton View Post
Just got to figure the right dcr for your heads/combo.
How do I go about that? From my internet research engines should be in the 7.5-8.5:1 for DCR? What factors effect what the DCR should be?
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Old 10-26-2012, 10:17 PM
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Originally Posted by ap72 View Post
400hp can be done with a very streetable combo using mostly stock parts. You have to be sure to NOT go too big though.

Run a basic 350 with flat top pistons and some 64cc chevy heads with a good clean port job and 1.94/1.5 valves. A used RPM intake, a good carb (650cfm+), good HEI ignition, and a decent set of 1 5/8" headers, and a cam in the 220ish range and all the lift you can get.

There really is no reason you couldn't get it built for less than a grand if you find a good core.
What are things to look for in a carb? It seems like there are a whole lot of options beyond the basic two and four barrel options I'm familiar with. What CFM range should I look for...what would start being to small and what would start being larger than what is necessary?
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  #49 (permalink)  
Old 10-26-2012, 10:40 PM
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Quote:
Originally Posted by 85jimmy350 View Post
What are things to look for in a carb? It seems like there are a whole lot of options beyond the basic two and four barrel options I'm familiar with. What CFM range should I look for...what would start being to small and what would start being larger than what is necessary?
I like a good running Qjet myself, mostly find them in 750 form, great throttle response, and decent econemy...
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Old 10-26-2012, 11:05 PM
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Quote:
Originally Posted by ap72 View Post
400hp can be done with a very streetable combo using mostly stock parts. You have to be sure to NOT go too big though.

Run a basic 350 with flat top pistons and some 64cc chevy heads with a good clean port job and 1.94/1.5 valves. A used RPM intake, a good carb (650cfm+), good HEI ignition, and a decent set of 1 5/8" headers, and a cam in the 220ish range and all the lift you can get.

There really is no reason you couldn't get it built for less than a grand if you find a good core.
That's what I've been saying all along, the only diviance is I love the 58cc 416 heads, with a maximum porting effort, and a 1094 head gasket with a standard flat top (small dish)gets you near perfect quench and lots of compression....and with the right porting will flow right there with a set of stock vortec's......your combo listed above is essentially what I put together for 800$ including machining costs....and I honestly cgouldnt have been more suprised or happy with it......I got piles of advice from everyone, but mostly abuse from guys I hang out with that have "good" parts.....well let me tell you, I just walked in the door from playing with a few of them tonight.....and the young lad with the biigest mouth is quiet now....as his g-body, with alum heads, airgap, Holley Carb, msd everything, roller cam, forged internal 355 just got schooled, not once, but twice, by my beat up, field car, with nothing more then left over, intake and stock qjet, and completely overlooked and under rated pissant 305 heads......nothing fells better then that, oh.....and I get better mileage then his as well......I felt 15ft tall tonight....everyone should get to put togethrt a motor that feels this good for such a small investment....it should be the poster child for reliable, budget do it yourself first build as far as I'm concerned....
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  #51 (permalink)  
Old 10-26-2012, 11:11 PM
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And the OP did say he had a perfectly good running 350 in his jimmy.......so hello....get your parts together, find the heads,do the research, and ask for porting advice from Fbird, then make a weekend of installing the parts and be hapy
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  #52 (permalink)  
Old 10-26-2012, 11:31 PM
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Originally Posted by 85jimmy350
"My parent's run a pawn shop so it's pretty easy to get tools for cheap. The job specific are a little harder but not impossible plus I don't mind buying to have around.
I have an 85 full size Jimmy. 700r4 transmission and 4.56 gears."
(the following is refering to vortec heads I believe)
"I am just looking through classifieds trying to find a guy who is trying to get rid of a set for cheap. I don't really have a timeline for when this has to be done. The 350 in my Jimmy runs fine. I was just looking for a project and I figured building an engine sounded like fun and it's something I would like to know how to do so in a couple years I can start teaching my son. Assuming I can find a well priced set in the classifieds would I need to replace the springs, valves, etc?"

85jimmy350,
First, I wasn't trying to scare you off when I listed some tools you'll need, but when you said you only had a $1-1.5K budget, I was just trying make you aware of some other expenses that you may not have considered as a
"newbie" if you will.
If you decide to buy some used vortecs, before you make a deal, stipulate in writing that they must pass a magnaflux inspection at the machine shop or you get your money back, or before you pay for them. They are known to be prone to cracking from age/overheating.
I'd have them "magged" and verify the guides/valve stems were in spec(diameters for oil clearance) before preceeding to port them. After porting and polishing chambers,then get a valve job(cutting/grinding valves/seats in chamber) and surfaced/milled just enough for gasket sealing(decks aren't very thick).
They also usualy require a bit valve guide cutting to shorten the height if you using a cam with over 0.450" lift at the valve with stock 1.5:1 ratio rockers, if you already didn't know.
Before you get that done, decide what cam will fit you needs along with the springs that the manufacurer recommends that will fit the heads, just in case you have to to machine the spring pockets for oversize springs(probably won't), but I'd still buy new springs. I being a bit "OCD" would also have them machined for screw-in studs(ARP) if your going to 400HP. I would also get some rail type roller tipped rockers, but that is one of the things that you may consider be out of the "buget" zone, where new stock type would suffice.
Thats going to cost a good chunk of your buget, but its spent where it will do the most good if your going for power. After adding up the costs, you may find that it cheaper/easier to buy a new set from Pace that have the valve guide mods along with new valves/guides/seats/springs/seals/clean decks, and not cracked, then you diss-assemble and port/polish. IMO the best way, but I'm sure some would dissagree as its not really a buget rebuild.
Aslo if your going to use a stock bottom end, at least have the rods resized and ARP bolts installed!
Here is a link that you ought to check out and download for future reference
IMO that will help you decide on your cam specs and compression.
Dynamic CR
Forgive the spelling.
Good Luck,
FWIW
ssmonty
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  #53 (permalink)  
Old 10-27-2012, 05:00 AM
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Quote:
Originally Posted by 85jimmy350 View Post
How do I go about that? From my internet research engines should be in the 7.5-8.5:1 for DCR? What factors effect what the DCR should be?
It depends on the type of heads and pistons. You want to make max pressure but not so much you get detonation.

For aluminum heads you can push the dcr a little further. You can run right on the 8.5 mark and be fine but for cast heads you need to be more carful with the dcr. It still needs to be close.

So figure for aftermarket aluminum good quaility heads and pistons you can go dcr of 8.5 to 1 and still be pump gas range for 87 octane. Maybe a little higher if running larger cams. And larger 210cc intake volume heads.

Cast heads of good quaility will Work in the 7.5-8:1 range. With 87-92 fuel in normal weather with properly work cooling system. Small radiator and 110 degree heat shoot for a safer number.

Crappy cast heads or pistons can cause detonation at lower dcr levels. This is where you have to pick out some heads and ask around about the best dcr for those heads.

To low of a dcr and you will never hit the number and the power band will be flat and boring. This is where you see performance rebuilds make 240hp with all the good part. You will need some compression to make 400 hp.

As far as carbs go i like the edelbrock/carter style the 1405 is good fair weather carb and easy to tune and rebuild. 600 cfm will easily support 400hp. And keep good snap and gas milage. I scored one off ebay to rebuild for 50 bucks it showed up clean and in working order. So not hard to find on a budget and new price is also easy to swallow if you need to buy one in a hurry.

A great working QJET is sweet and a beautiful thing. A bad working one is so bad plpl have shot there qjets. This does not happen with holley or edelbrock. They are also a **** to rebuild and work on. Keep it simple.
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Old 10-27-2012, 06:53 AM
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85jimmy350,
One other thing I should have mentioned is that if you have the rods resized, get the machine shop to back off the rod bolt nuts a couple of turns and break the caps loose from the rods. The bolts are knurled for a tight fit and its hard to get the caps off, well it has been for me anyway more than once. Its not so hard to do when the pistons are in the block, and on the rods, and the rods are on the crank.
There is another tool you'd need to break the caps off of stand alone rods unless someone has a method that they might share that doesn't damage the rod.
Thats just one more reason I like rods with cap screws instead of thru-bolts, but that doesn't fit in a buget build.
That leads to another issue someone may shed some light on. If your using Plastigauge to check rod clearance, doesn't it get distorted when you use a hammer handle or some other rod to hit the bottom of the piston to break the rod cap loose? I use mics and bore gauges to check.
Another tool that would really help you to pick the correct cam for your build
is Comp Cams "Camquest" software that has a built in dyno simulation. I can't say how accurate the dyno function is as far as real life numbers, but its a good tool for comparing different cams per the engine parameters you provide. It also has the various cam specs that you can enter into the compression calculator that I previously provided a link to. You said you wanted to learn about engines, and I belive these two pieces of software can really help you to make your own decisions based on your particular circumstances, instead of what someone on the net reccomends. They won't be the one that has to live with it.
I'm no expert, and I find these two pieces of software extremely useful. Again pleae forgive the spelling.
FWIW
ssmonty
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  #55 (permalink)  
Old 10-27-2012, 10:49 AM
How fast is fast enough?
 
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Quote:
Originally Posted by bygddy View Post
That's what I've been saying all along, the only diviance is I love the 58cc 416 heads, with a maximum porting effort, and a 1094 head gasket with a standard flat top (small dish)gets you near perfect quench and lots of compression....and with the right porting will flow right there with a set of stock vortec's......your combo listed above is essentially what I put together for 800$ including machining costs....and I honestly cgouldnt have been more suprised or happy with it......I got piles of advice from everyone, but mostly abuse from guys I hang out with that have "good" parts.....well let me tell you, I just walked in the door from playing with a few of them tonight.....and the young lad with the biigest mouth is quiet now....as his g-body, with alum heads, airgap, Holley Carb, msd everything, roller cam, forged internal 355 just got schooled, not once, but twice, by my beat up, field car, with nothing more then left over, intake and stock qjet, and completely overlooked and under rated pissant 305 heads......nothing fells better then that, oh.....and I get better mileage then his as well......I felt 15ft tall tonight....everyone should get to put togethrt a motor that feels this good for such a small investment....it should be the poster child for reliable, budget do it yourself first build as far as I'm concerned....
The 416 heads... Well if you want you can run them but even after putting money into cutting the seats and new valves, and all the time into porting you're ALMOST as good off as you are with bone stock Vortecs.

To me its just a waste of money as you can usually find used Vortecs for $100 a set now and just cutting your larger seats in the 416's will run that much or more.
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  #56 (permalink)  
Old 10-27-2012, 06:58 PM
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thanks for the help in the mail issue ap72
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Old 10-27-2012, 07:08 PM
How fast is fast enough?
 
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thanks for the help in the mail issue ap72
np, sometimes things are a little more complicated than they should be.
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  #58 (permalink)  
Old 10-27-2012, 08:58 PM
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Originally Posted by 85jimmy350 View Post
How do I go about that? From my internet research engines should be in the 7.5-8.5:1 for DCR? What factors effect what the DCR should be?
DCR varies with the calculator that you use. I have used the one on Keith Black Piston's site for decades, so each time the result is comparable to any other time I use it. On that calculator, I limit DCR to around 8.5:1 for pump gas. You could probably go a little higher and be ok, but I like to err on the side of caution. If I know that cat pea gas is all that will be available, I'll use a number more like 8.0:1 DCR.

What actually governs the DCR that you build into a motor is the fuel that will be available to operate it. If you build a high DCR and then you can only get cat pea fuel, you're in trouble. If you build a low DCR and then you can only get cat pea fuel, you'll be fine.

I always try to counsel young men that the motor is a COMBINATION of parts that must be chosen to WORK TOGETHER toward a common goal.
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Old 10-27-2012, 10:10 PM
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It seems like maybe spending $500-600 on a decent set of new head might be money well? I don't really know what to look for as far as damage goes and it seems like by the time I take them to a machine shop and have the magnafluxed and I buy new springs and what not. I might be better served just buying a new set and giving them a port and polish. What do you guys think? Like maybe the ... Chevrolet Performance 12558060 Chevrolet Performance Cast Iron Vortec SBC Heads they are cast iron...how much difference would aluminum make?

As for those of you who have replied about the DCR, I'm planning on running 91 octane pump gas (I'm already used to paying for it cause I get a dieseling effect in my jimmy if I use 89 or 87 octane...speaking of which do any of you guys know how to fix that?) I don't want to push the DCR right to the limit so 8.2 area should be good right?

Carbs... I'm rebuilding the 2G QJet that came with the engine and it's pretty straight forward. How much more complicated is say a Holley or Edlebrock 4 bbl?
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Old 10-28-2012, 08:02 AM
How fast is fast enough?
 
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Originally Posted by 85jimmy350 View Post
It seems like maybe spending $500-600 on a decent set of new head might be money well? I don't really know what to look for as far as damage goes and it seems like by the time I take them to a machine shop and have the magnafluxed and I buy new springs and what not. I might be better served just buying a new set and giving them a port and polish. What do you guys think? Like maybe the ... Chevrolet Performance 12558060 Chevrolet Performance Cast Iron Vortec SBC Heads they are cast iron...how much difference would aluminum make?

As for those of you who have replied about the DCR, I'm planning on running 91 octane pump gas (I'm already used to paying for it cause I get a dieseling effect in my jimmy if I use 89 or 87 octane...speaking of which do any of you guys know how to fix that?) I don't want to push the DCR right to the limit so 8.2 area should be good right?

Carbs... I'm rebuilding the 2G QJet that came with the engine and it's pretty straight forward. How much more complicated is say a Holley or Edlebrock 4 bbl?
060 Vortec heads are POS- the bowtie ones are great though. The 060 one have crappy seats, thin castings, are prone to cracking, and dont flow what the originals did (062 and 906 castings).

As for edelbrock carbs- they may be the simplest carb to rebuild and tune for street use. I highly recommend them for a street engine, especially if you're a rookie.
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