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Old 10-21-2008, 12:09 AM
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SBC Motor Build

I figure 8 race and was looking to build a motor over winter...I used to race in the unlimited class but funding is low so im dropping down to a stock class...The rules for a motor are very simple...Pump gas only, stock motor(pieces), and must pull 15 in. of vaccuum at 1000 rpm....also cast iron intake....


So i kind of have some ideas on where to go but would like some help...I have a 327 block/crank/ and 462 heads, also a 305 block and 305 heads

i also have 1 993 head and 3 882 heads that made over 400 hp and were good up to 7200 rpm..one set was on a 406 sbc and the other was on a 355 sbc

anywayz i was wanting to get a either a 283 or 302 crank(have to figure out if i have a LG or SM journal 327 yet) and stick it in the 327 block...then i was going to put 6" rods in it(I have heard of some 5.94 rods that were stock in like early 90's caprices?? would these be good)...I have a feeling that finding a 283 or 302 crank is going to be expensive though so i might stick with the 327 crank and just live with like a 1.83 R/S ratio instead of the 1.98 with the 3" stroke crank

for pistons i have no idea...i have some that came with the 327 don't really know what they are...would i have to go aftermarket to fit a 6" rod(or 5.94) in the 327??

for heads i heard the double humps would be really good but they would pry have to be gone through and the others are pretty much race ready

cam and lifters would most likely have to be hydraulic..any suggestions for the cam?? ik this is very important for being within the vacuum limit...i read that if you overlap the valves a little you can kind of cheat?? also by tightening your valve lash?? i'll have to reread my article in stock car racing but there was a good article about vacuum in it

for an intake i either have a 2bbl or 4 bbl so that's really not a concern..i can't run adapters so if i go 2bbl i would go a 4412 holley and the 4 bbl would be a qjet with some special "race" mods done to it

any help would be appreciated...really hopin to not spend much money on this build thats why i was thinking about sticking with the 327 crank and using the 327 block...Ik i said they must be stock pieces but i could get away with some aftermarket pieces if needed cuz they dont' strip down the block....Mainly the only rule i want to adhere to is the 15. in of vacuum

mainly I want fast revving torquey motor so i can accelerate out of the corner good...will pry be hooked up with 3.30-4.11 gears and will be pulling around a 3000-3500 lb midsize monte carlo

edit: you can suggest your own good combo's as well...i have access to a 400 and a 350 and a 87+ 350...i was going with this combo based off of what i have read in smokey yunicks book stating that the better R/S ratio you can get the more low end torque and faster acceleration you will have

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Old 10-21-2008, 01:45 AM
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SBC build

Using a 3" stroke crank is'nt going to make it a "torque" motor; it will like to rev, but you'll need a valve train to keep up with it. There are spacer bearings that allow you to put small journal cranks into large journal blocks, and large journal rods onto small journal cranks. Is there a CID limit for your class? Build the biggest motor you can, it'll be cheaper than a 301/302. But, if you're sold on building a 301/302, then use a 327 or 350 block with an early 265,283,302 crank. The large journal 302 crank will be costly. Use the spacer bearings. With your 5.94 rods you can use a 350 piston, an it'll be .025 in the hole; or you can deck the block. You can also do this using the LATE 265 crank and rods, with a 350 piston, in a roller 350 block. But, that assembly will be a cast crank. Can't beat Votec heads compared to the old camel humps, but, Vortecs will limit the use of domed pistons; use flat tops. Why put a lot of money into an engine going into a figure 8 car that most likely will sustain a lot of body/frame damage? I thought these cars were built on the cheap, so-to-speak.
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Old 10-21-2008, 07:42 AM
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If you want a torquey motor then go for max. displacement- cubes matter FAR more than rod ratios, and even the biggest rod fanatic/lunatic will admit that. A simple 400 build with Vortec heads cleaned up and milled .040", flat top pistons, and a cheap solid circle track cam will get you more than enough torque and power. a LOT more than a 302 with twice the money put into it. The problem will be with finding a cast iron intake for the vortec heads... You may want to get some AFR 195's instead if you can spend the extra few hundred dollars- which it sounds like won't be a problem if you're looking to build a 302.
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Old 10-21-2008, 10:41 AM
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thanx for the reply's and I'm pre new to the whole motor thing...I knew the 302 crank would be expensive so thats why i thought I might go with the 327 crank...Didn't a stock 327 put out around 300hp?? Are vortec heads still cast iron??(clueless on new motors) if i went with the vortec heads should I just build a 87+ and have everything roller??

And if i can't find a cast iron intake for the vortec heads which heads would you bolt on the 400?? if i went with he 400 i'd pry bore it out to a 406 and re-use some of my old pieces from my blown up 406 i had...

Figure 8's around here have changed quite a bit over the past few years..it used to be knock out some windows throw in a cage make sure the motor will run and go to the track... now its all about high dollar drivetrains...and im really not worried about the motor getting wrecked because i run oil and temp gauges and theres enough plated steel up front to protect it...if anything i will just ruin a 150 dollar aluminum radiator

also this is kind of a budget build....figured it would be cheap because i have to use all stock parts

once again thanks for all the help guys
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Old 10-21-2008, 11:10 AM
How fast is fast enough?
 
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there is an iron intake for Vortec's- 14097499 (you better port the hell out of it though as it is VERY restrictive). With the vacuum rule and such you have a few options- a vortec 350 on a roller block, a 383 on a roller vortec block, or a non roller 400. all things considered you'll probably be able to maek more power with a hyd. roller cam in a 383 than a hyd. flat cam in a 400 BECAUSE OF THE VACUUM RULE. If it wasn't for that I'd say run a solid flat tappet cam in a 400 for good cheap power. That Vacuum Rule is going to biggest PITA for this build. I recomend using a hyd. roller cam and total Seal Gapless rings to help with that. Those rings are definitely worth the extra money. A flat top 383 with 5.7" rods and vortec heads is a great start to 500+ hp.

A iron manifold and the 15" are going to be your biggest hurdles but its the challenges that make racing fun. Go with some LT1 rods and upgrade the Vortec heads with LS6 springs and retainers.

They should pay me for this.
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