Squeezing power out of my chev small block

D.I.W.

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I'm currently in the middle of a (very messy) cam swap for my 5.7 chevy 350. Putting a comp cams 291 in with several complications, but after a grip of brakleen and nylon brushes its ready to go in. While the beast is torn apart i've had time to think of the little things that might help with performance, such as intake and ignition (i know the block doesnt need to be torn apart for these, but might as well when i throw it all together.)

The cam did come with new valve springs (ls1 springs to be exact). and i have a new timing kit and lifters. Should i bother with rockers (just go roller?) and new pushrods? Would new valves help also? We are doing a valve leak check on sunday before it all goes together. Any input would be greatly appreciated. Thanks!
 

scottm

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What is your application and year? That is a lot of cam for some uses. If it has more than about 50K miles on it I would go ahead and do a valve job. You definitely have to replace the springs, and I would put on COmp Cams Magnum roller tip rocker arms. Stock rockers will waste the guides with a high lift cam. Also read this thread post 14 for some other ideas.

http://www.race-dezert.com/forum/showthread.php?t=68555
 

johnnyweb

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What heads are on the engine? Also Intake and Carb specs will help us know what you got.
 

D.I.W.

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i'll look into specs, its a 92 c1500 2wd. TBI, not sure what type the heads are. I have LS1 valve springs to eliminate (hopefully) valve float. we're doing a compression check before we put it back together. All new seals going in, minus heads unless they're leaking.

Engine was "Rebuilt" 50k ago, but it was such a mess when we started that we quickly decided that the guy i bought it off of was lying his ass off. Either way i got it cheap.
 

D.I.W.

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My guru says...

194 intake
180 exhaust

whatever the stock setup is for that engine
 

Tipracer

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its a SBC....SO MANY POSSIBILITIES....
 

scottm

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92 Tbi? Bummer... Does it have to meet emissions? Unfortunately the tbi engine has some of the worst heads chevy has ever made. Heads from a 96 to 99 vortec 350 are much better. But then you will have to drastically improve everything else, from the fuel pump to the tbi system to the exhaust to the chip in the computer. It is much tougher than the long-gone carb days. Just changing the cam or adding headers requires a reprogrammed chip. And that particular cam will run especially bad with the stock tbi. Low idle vacuum will make it think its under heavy load, so it will dump in too much fuel. I would reconsider everything you are planning to do. A better idea is to swap in a complete 96-99 vortec engine including the computer. But here are some links to upgrading the tbi, which will be the first place to start for improving that particular system. I spent a year going through this. I have a chip burner, tuning software, and everything else for tweeking the tbi, and frankly its not worth the effort for big cams and hi perf. Sorry.

http://www.xtremefi.com/QA.htm
http://www.diy-efi.org/gmecm/
http://www.affordable-fuel-injection.com/index.php?id=2&title=Fuel+Injection
http://tunerpro.markmansur.com/
 

mebuildit

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Unless you already have roller lifters, ALWAYS replace your lifters when doing a cam swap. Depending on the heads, mileage and use, check for flatness make sure that you clean as much carbon buildup off as you can. If you do decide to put new valves in it, clean up the heads some. ie take and just smooth some of the ports, try not to remove a bunch of material or get the Vortec heads? Are those valve springs designed for your head style? Beehive springs are ok, just have to be careful with clearance at the base of the spring. There are plenty of people who can tune your computer.
Also, a good site to learn stuff is: www.ls1tech.com

Just my .02¢
 

griffin #11

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if you wanted to go all out you might want to put some nice pair of alumium heads with msd ignition with an intake matched to your heads...that will get you some big gains.
 
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