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1st SBC 350 Build

9K views 74 replies 11 participants last post by  Nateloggg 
#1 ·
New guy here. Hoping you guys can give me some advice on a 350 build. I have never built a motor before, but I have been reading alot about it. Being broke all the time has taught me that I can fix most things if I have too, even if it takes me a couple tries.

I have an 84 Chevy c10 4x4 with a 305 in it currently. Also has 700r4/208 with stock staul , 3.73 gears and 31" tires. My line of thinking with this build is best bang for my buck. Most of my parts so far have come from helping my Grandpa clean out his garage.

So far I have:
010 4 bolt block
Stock crank
edelbrock performer intake
635 carter 4 barrel carb
1 5/8 full legth headers with 3" collector_ G-Pa thinks they might be
from an old Camaro
2 1/4 inch duel exhaust. stockers from you-pull-it
Double row timing set, performance gasket set and some Napa lifters from 1986 NIB, 16 stock rods dissasembled in a milk crate

I had a set of 882 (1.94/1.5) heads that looked to be in desent shape. I took them to a guy Grandpappy reccomended for rebuild. He found that one of them was cracked pretty bad behind the center 2 exhaust seats. He found a set of used summit heads laying around and rebuilt them for me instead. I am not 100% on the volumes of the heads, I believe 72cc and 165 intake runners. They have 2.02/1.6 valves. Has a "DRT007" cast. Looks like he did a nice valve job with back cuts. He also threw in an extra set of roller tip rockers and gave me two sets of springs. One he said was stock vortec rates, and the other was heavier. Can't remember exact rate. All for $180

So that is pretty much what I have so far. I have not settled on a cam or pistons. The truck will be for all around use. Hauling fire wood or quads, occasionally off road play, and of course blowing the doors off of little rice burners. I guess my questions are:

What would be a good compression ratio to shoot for and cam/piston combo while still running on pump gas? Prefer 89 octane or less.

Will the 2.02 valves hurt my bottom end performance in my long bed Chevy? If so, how much? I don't want a slug.

Is there port/polish tricks to increase low end torque?

Is it ok to use the old/new hydraulic lifters with a bigger cam?

And of all my parts so far, are there any that should be avoided or replaced with something else to better suit my needs?



Thanks in advance.
Nate
 
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#2 ·
I am hoping that I can go 9.5:1 on 89 octane?
Been looking at a few cams:

112571-12CL112571-12269279215225.455.465112108112571-12CL112571-12269279215225.455.465112108Howards 112571-12
269/279
215/225
.455/.465
112/108

Lunati Voodoo 10120701 or maybe 702

Crane Energizer 266H10 or 272...
I figured I would pair one of these or similar to some 2VR flat tops.
Any thoughts?
 
#3 ·
Cam and compression walk together, You need to be able to calculate two compressions the Static Compression Ratio (SCR) which is nothing more than all the cylinder volumes (piston sweep, shape volume of piston crown forming the floor of the combustion chamber, clearance between piston and deck, head gasket, combustion chamber) divided by the volumes above the piston at TDC and any volumes of its crown (shape volume of piston crown forming the floor of the combustion chamber, clearance between piston and deck, head gasket, combustion chamber). Then compute the Dynamic Compression Ratio (DCR) which is the same calculation as the SCR except the sweep volume of the piston is reduced by the stroke used up when the cam closes the intake valve in crankshaft degrees.

Sweep or swept volume of the cylinder is bore area (pi times bore radius squared) times the stroke length.

Generally the DCR is good at 8 to 1, this can go up to 9 to 1 but a range of head materials and combustion chamber shapes needs to be considered. Open chambers and cast iron need to favor the lower end of the scale, aluminum and closed chambers can favor the higher side.

The DCR calculation tells you what the SCR needs to be to compensate for the piston movement at the point of intake closure. This is a lengthy trigonometry calculation as piston movement is not linear to crankshaft degrees and it involves the length of the connecting rod to compute. You need the also know the cam's events, specifically in crankshaft degree when the cam closes the intake valve. Since the DCr doesn't consider the effect os the cams LSA beteen lobes or the LCA of the lobes or the effects of rocker ratio the computaions are not as complete as they could be but what it does compute is sufficient to derive the needed SCR to optimize the DCR and mitigate the effects of long duration cam timing by minimizing torque loss typical of these cams. Since the DCR is pretty involved math using one of the one line calculators such as Keith Black's

http://www.kb-silvolite.com/calc.php?action=comp2

This calculator prompts you to add 15 degrees to the closing point if it's stated as measured from .050 inch of lift. This is good for modern fast ramp cams like the Lunati VooDoo or the Comp XE series. But cams with longer ramp profiles as used a lot by Summit, Howards, ELgin and many others including some lines of Lunati and Comp it is necessary to add another 10 to 15 degrees for ramp below .050 to true zero lift.

Bogie
 
#4 ·
Cam and compression walk together, You need to be able to calculate two compressions the Static Compression Ratio (SCR) which is nothing more than all the cylinder volumes (piston sweep, shape volume of piston crown forming the floor of the combustion chamber, clearance between piston and deck, head gasket, combustion chamber) divided by the volumes above the piston at TDC and any volumes of its crown (shape volume of piston crown forming the floor of the combustion chamber, clearance between piston and deck, head gasket, combustion chamber). Then compute the Dynamic Compression Ratio (DCR) which is the same calculation as the SCR except the sweep volume of the piston is reduced by the stroke used up when the cam closes the intake valve in crankshaft degrees.
Ok Bogie. So I suppose the rod length (5.7") is more valuable information then the fact that they are stored in a milk crate. I plan on decking the block to the installed piston height or total clearance of .040 with head gasket,...1.5 rockers, and bore .030.

Sweep or swept volume of the cylinder is bore area (pi times bore radius squared) times the stroke length.
The sweep volume is approximately 44.375 cubic inches.

Generally the DCR is good at 8 to 1, this can go up to 9 to 1 but a range of head materials and combustion chamber shapes needs to be considered. Open chambers and cast iron need to favor the lower end of the scale, aluminum and closed chambers can favor the higher side.
So by this statement, I assume that with my iron heads, I can shoot for 8-8.5 dcr safely. I asked about 89 octane, but you do not specify. Are you figuring with 92? pump gas? I understand that there are several other factors in avoiding detonation...

So your link did not work for the DCR calculator. I used this one to calculate instead.
https://www.uempistons.com/index.php?main_page=calculators&type=comp
Using the lunati 10120701 specs and this formula to estimate IVC. (intake at .050)213/2+LSA(112)-Ground in advance (4)-180; I came up with 34.5*
The dcr calculator came up with 8.413 DCR using SCR of 9.525. Does this look correct?
 
#6 ·
I have just a hair over 9:1 with 64cc iron heads and slightly dished pistons. I only run 87 octane and don't have any detonation problems. Also a truck motor running an Edelbrock 1406 and a Summit K1102 camshaft.

The connecting rods need to be indexed, meaning they have to go in the same direction and orientation that they came with from the factory. If your rods are just loose, that might be a problem that needs to be sorted out by a machine shop.

I agree that it's good to shoot for around 9:1 with a stock-ish motor. Will give better fuel economy and power, and is close to what the Vortec motors came with.
 
#7 · (Edited)
. Hello... welcome... Where are you located? Around here gas grades are only 10c difference and the better gas MPG of a higher compression engine more than makes up for the slightly higher price...

. I'd aim for 9.5-10:1 and just use the gas grade to match...

. Your 215/225 cam choice looks like a good one... or a Summit K1103 214/224... (they may actually be identical)

http://www.summitracing.com/parts/sum-k1103

. Instead of decking the block, I'd just use good KB pistons that have a properly tall 1.560" or higher compression height:

http://www.summitracing.com/parts/uem-9901hc-030

. Or the KB 9902 or some mini-domed ones, depending on actual head chamber size...

. These parts should get you into very streetable 350-400 HP depending on head flow capabilities... 2.020" valves don't hurt anything...

. Most exhaust manifolds and headers just plain don't fit with a V8 in an S-10... oh, I'm sorry, you said C-10...

. What's a 208 on your tranny? Part number?
.
 
#8 ·
For the use you stated,keep the SCR @ 9.5:1 max.Shoot for a DCR of 8.2:1.Hauling wood,off roading,or any heavy loading @ low speeds won't like any more compression than that.You would only be asking for trouble.With the 72cc heads,you have some room to play with & could get by with flat tops vs a D cup which costs more & is usually necessary w/ 64cc heads to keep SCR/DCR in ck on a build such as this. The 2.02 valves are not necessary for what you're building,but,won't hurt much. They may hurt low speed torque slightly,but,nothing you would feel.Don't use either of those spring sets w/o knowing the specs for them.Buy the proper springs spec'd for the cam you use.They're not that much money.
 
#10 ·
Thanks guys for all the info so far guys. I am that much closer to not screwing things up.

The weaker springs I planned on using for cam break in. The others are actually 110lbs @ 1.7 with 357lbs/in spring rate with .480 max lift. So I guess if they don't work I'll toss em aside. I didn't have the info handy earlier.

It's good to hear that the 2.02's won't hurt torque much. I had read that it could....
 
#11 ·
With a 4.030 bore,72cc head,5 to 6cc flat top,& a .040 quench,you will be @ approx 9.4:1 SCR.Using a cam with an IVC @ .050 lift of approx 35*,will give you a DCR of 8.25:1.That would be a good spot to be in this build & the intended use of your truck.It will have good power & can still be used as a truck.IDK a lot about those heads,but,I would call Summit to try to get some specs on flow.Find out @ what lift they reach max flow,& choose a cam/rocker arm combo to hit close to that lift.With 165 cc intake ports,they're not gonna be high rpm power heads.
 
#12 ·
I live in the sticks just north of Vancouver, WA.

I have been looking at KB pistons, but I was having a hard time deciding on them since there price seems to have gone up 100-$200 for a set in a little over a year. I will probably go this route though. I try to get all made in USA stuff if I can.

As for the 208, that is the transfer case. np208. The transmission will probably be a thread for next year.
 
#13 ·
KB's are good pistons.Just pay close attention to & follow directions on ring gap.KB's place the the top ring higher up the piston which builds somewhat higher heat on the top ring.This requires ring gaps to often wider than normal to prevent the rings from butting together.
 
#15 ·
Got any info on rod indexing?

The heads are supposed to be a Dart casting.
Intake @ .500=210scfm
Exhaust @ .500= 138scfm
Can't find any low lift numbers.
Casting seems really good. A couple ridges on intake and exhaust I guess from throats being cut? There is a ridge behind the exhaust seats also. Think it would be worth cleaning up the exhaust to get a little better flow?
 

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#23 ·
The "DRT007" casting is a Dart Stock Replacement type casting.

Clean-up porting/"bowl blending" is definitely worth it, along with streamlining/slimming that fat valveguide boss in the valve bowl. Just take a look at some porting advice and pictures to get an idea of basic simple clean-up for those area's, it isn't hard if you want to take the time and could get you 20-25 cfm intake and 40 cfm exhaust...a real noticeable improvement even a beginner can get if you want to spend the time doing it.
 
#16 · (Edited)
Thanks for the piston recomendations Joker

Find out @ what lift they reach max flow,& choose a cam/rocker arm
combo to hit close to that lift.With 165 cc intake ports,they're not gonna be high rpm power heads.
To do this, I assume I would need more flow numbers, then calculate the amount of air pulled into a cylinder at optimal lifts taking rpm range and cylinder volume into account? It seems like there could be quite a few other factors involved in this as well, like every thing bolted to the engine, vaccuum, back preasure...

Do you happen to have a calculator to estimate how this is done?


THANKS OldBogie for your DCR/SCR/cam timing explanation. During my first read through, I figured you wer just being a
********,:confused: but after breaking it all down, it really made alot more sence.
 
#20 ·
Thanks for the piston recomendations Joker



To do this, I assume I would need more flow numbers, then calculate the amount of air pulled into a cylinder at optimal lifts taking rpm range and cylinder volume into account? It seems like there could be quite a few other factors involved in this as well, like every thing bolted to the engine, vaccuum, back preasure...

Do you happen to have a calculator to estimate how this is done?


THANKS OldBogie for your DCR/SCR/cam timing explanation. During my first read through, I figured you wer just being a
********,:confused: but after breaking it all down, it really made alot more sence.
Try Wallace Racing site for various calculators.Lots to choose from.My point about on the head flow was to help you get max flow potential w/o overkill on lift.If they hit max flow @ .500,it will not help any by using a .550 lift cam.Same thing for cam.Use a cam with operating range that compliments the heads,SCR,etc.If the heads make power to 5000 rpm,using a cam that makes power to 6500,won't do you any favors.Matching parts makes more power,efficiency,realiability,than big parts.
I would reconsider that exhaust tho.2 1/4" will choke you off.
 
#19 ·
You are right. For this build, I will keep it mild for sure. but I can't help but dream about the next one a little. I see a roller motor in the future.

Reading all the threads about crappy oil, "cat pi$$" fuel, and flat tappet nightmares is keeping me a little cautious.
 
#21 ·
Lot's of good stuff at Wallace racing. Thanks Joker

So I am planning on going with 5-6cc 2vr pistons. Putting me at 9.4-9.5 SCR. I am leaning towards the Howards cam 112571112 215/225@.050 and 455/465 lift. I have 2 concerns though.
1. With my 700r4, 31' tires, 3.73 gearing and cruise speed of 65mph, RPM's are:
O.D.=1840rpm
3rd = 2630rpm
2nd= 4287rpm
I am not sure where my torque numbers are at with this cam or where they should be? Can some one help me out with a torque curve? Would be much appreciated.

My 2nd concern goes back to the exhaust port on these heads. If you look in the port, it looks like the heads were cast for 1.5" valves and 1.6" seats were just slapped in. There is a perfect 90* step in the cast all the way around the exhaust seats, about .050" wide. I assume this will collect heat here. But do you think it would be enough to worry about?
 
#22 · (Edited)
I was trying to upload an RPM calculating spread sheat to share, but I couldn't get it to work. Here is the formula if any body wants it.

Engine RPM = 63360 / (Tire size in inches x 3.14) x (MPH)/60 x (Trans Gear Ratio) x (Axle ratio)

I know there are online calculators out there, but I like to know how these things are calculated.
 
#24 · (Edited)
.
. X 2... Getting rid of those ridges will help flow and eliminating the exhaust ridges will also prevent some exhaust heat going into the heads instead of out the exhaust pipes... if have access to or own an air compressor, then a $10 air die grinder and a $10 carbide bit will do that job... just be careful not to accidentally touch the valve seats, even for a fraction of a second...

. Your 215/225 cam is fairly mild, but spirited, and should pull well from 1500 - 6000 RPMs...

. It's good you know how to calculate RPMs vs MPH, but this slick online calculator will give you a spreadsheet of info for every gear at every 100 RPMs in a fraction of a second thanks to modern computer power that would take you a month to do manually. And the variables can be changed/experimented with and new results obtained again just as quickly. It also gives tire diameter from the tire size spec.s:

http://www.f-body.org/gears (hit 'clear right' button each time before doing anything)
.
 
#25 ·
Seems like I am saying thanks an aweful lot around here, but you guys kick asphault imo. I have learned alot in the last couple of days.

I found a guy who will flow my heads for a couple bucks. i will try to get a base line figured and post the numbers here later. I do have the die grinder and air (and time). I few weeks ago I was practicing on the cracked 882's when I ended up with a chunk of metal in my eye. The doctors visit to get it out kind of sucked my part money right out of my pocket. A little slow to get back on that horse.

As for the pistons, I found KB's to be Hecho In Mexico. And the Summitguy I talked to HinteD that their pistons were made by sealed power/Fed Mogul, and were also made in Mexico. I will keep looking for that USA made set of budget pistons.
 
#26 · (Edited)
Seems like I am saying thanks an aweful lot around here, but you guys kick asphalt imo. I have learned alot in the last couple of days.
Nate, you've learned a lot because you are open-minded and willing to learn. We like that. :thumbup:

I found a guy who will flow my heads for a couple bucks. i will try to get a base line figured and post the numbers here later. I do have the die grinder and air (and time). I few weeks ago I was practicing on the cracked 882's when I ended up with a chunk of metal in my eye. The doctors visit to get it out kind of sucked my part money right out of my pocket. A little slow to get back on that horse.
Been there, done that. A good pair of safety glasses start to look cheap after contributing to the doctor's old age fund. :eek:

I will keep looking for that USA made set of budget pistons.
I remember Badger Pistons from my youth, but haven't seen anything about them for many years. I was just reading that their foundry and machining operations are in Mississippi, but can find no online catalogs to browse through. The folks in this link I'm providing for you are sellers, so maybe if you contacted one or two of them, they could get you a catalog mailed out or to a website where you can look over the Badger line.
Badger Pistons, Warehouses

I'm pretty sure that as you continue your quest for the truth in cylinder heads, you will discover that the secret to runner design is not size, but shape. Take the L31 Chevy head for example....Its little 170cc intake runners can flow more mixture than some 200cc runners in some other heads. The way I see it, choosing of a cylinder head is a matter of selecting the proper size and shape of runners that will coordinate with the cam so that both of them run out of poop at about the same rpm's. It'll do no good to use a set of heads that will pull to 6500 if your cam signs off at 5500 because that would mean that the heads are too big to provide lower rpm cylinder filling as a result of decreased velocity. Flow would, of necessity, be slow at lower r's. Vice versa, it makes no sense to use a cam that pulls hard to 6500 if the heads stall and sign off at 5500 because that cam would be giving up power at the bottom. A street motor that makes power all the way through the rpm range, whatever that range is, based on gearing, tires, etc. is the motor that will be quickest. That's one of the things that most newbies don't understand. All they see is the max hp at a certain rpm, not taking into consideration that the motor must also make power all along the rpm range to be moving the vehicle at a maximum rate of acceleration.

.
 
#27 ·
While I'm thinkin' about it, I will advise you to add ground straps on the car. The motor must be grounded to the subframe and the body. The subframe must be grounded to the motor and the body. The body must be grounded to the subframe and the motor. I like to choose a place on the passenger side footboard to drill a hole for a bolt and nut to hold one end of a grounding cable to ground the body. Pay attention and don't drill through any other components. Grind off all paint on the inside and outside of the sheet metal, a patch big enough to allow the cable end to be pinched on bare metal. Attach the ground strap to the footboard with a bolt and nut. Smoosh RTV all over the connection, on the motor side of the floorboard as well as inside the cab. The RTV will wet-proof it so it will not corrode and ruin the connection. Now, drill a hole in the subframe for the other end of the body ground cable and grind off all paint and nastiness down to bare metal. You will attach the other end of the body ground here, as well as one end of the second cable that will go from the subframe to the motor block or cylinder head. It takes only 2 cables to tie all three components together. If you don't do this, trust me, you'll have electrical problems that you will never find. A vehicle can never have too many grounds.
 
#28 ·
Some VERY good advice from Techinspector1 concerning the grounds! And yes, I learned it the hard way too! Replaced an engine in one of my circle track cars, we were in a hurry, thrashing to get it done to go racing that day, and inadvertantly left off a ground strap to the engine. Wouldn't crank when it was hot and had to be push started. Didn't want to run right after it was push started til we finally found the problem.
 
#30 · (Edited)
.
. As far as I know, KB pistons are better pistons that Keith Black had spec'd and specially made by United Engine & Machine/Silvolite/KB/Icon in Carson City, Nevada... unless something changed... my KB 151 .030" pistons box says Made in USA, but I've had them a long time in my 425 HP 351W engine in my boat that I often hold at WOT for several minutes at a time on Great Lake Erie or the Maumee River... Keith Black has died but he was a famous and totally respected TopFuel Dragster aluminum Hemi engine builder...

United Engine & Machine Co. Incorporated, Performance Pistons

http://en.wikipedia.org/wiki/Keith_Black_(engineer)
.
 
#31 ·
I was wearing safety glasses at the time. But I was cheating, trying to peak around fogged up glasses. Now I upgraded to a set of goggles.

That was a good rpm calculator Buzz. I was trying to do the same thing, but I am not that good with excel.

I went and looked into flowing the heads and found that a couple of bucks to one guy wasn't a couple of bucks to me. They did only want $20 to flow a cylinder, but what wasn't mentioned prior was that they wanted $180 just to set up the bench. Seemed like my money would be better spent else where, so I opted out.
 
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