Is it worth trying to rebuild my 5.7 350 '94 truck engine w/tbi? I wanted to increase performance a bit, but seems like not a lot out there for this engine. It's been a good truck, is paid for, and I wanted a new hobby. I've previously added headers, chip, power pulleys, etc., bolt on stuff, but I wanted to try and rebuild. I'm new at this, but I can read a book and follow directions. Any advice would be appreciated.
if you have the swirl port tbi heads (not sure what years they used them on)you'll most definatly not want to reuse them. basicaly if you pull the intake valve you'll be able to see a ramp that induces extra swirl into the intake flow.it restricts the intake port valve pocket, and extremely chokes off the flow. these are some of the worst flowing heads chevy made.suposedly to induce swirl, and reduce detonation. but if they worked as there suposed to, then why did g.m. have only 9.4:1 compression with them, why not run more compression. they flow like 198cfm intake, at .500"lift. secondly if you have the monie, i'd upgrade to a roller cam.better economy/more power= it's a win win.i'd get some really good heads (do your research, with flow numbers) i like afr,trickflow,and patriot performance. but thats just me.finaly when you have it all worked out, i'd get a custom tailored chip.94 might have the programable ecu, lt1's had a programable plug, and play prom. idk what year they made the switch to a writable cpu.i should research that too. mayhap another time.
someone already sked this, on either hotrod, or carcraft.it was answered very thourghly.like a marine tbi has 2" bores vs. ours which have like 1 7/8" i think.marine throttle body is much bigger, and higher flowing.they had a gm part number for a decently priced 350 vortec.aperantly not all vortec heads flow as well as i previously thaught. so make sure you know which ones your getting if you go this route.again see hotrod, or carcraft. i think 059 was the bad flowing one.sometimes these magazines are invaluable. if it were mine, i'd get srp flat top pistons, with 2 valve relievs 4cca set of 64cc chamber heads, good flowing. comp cams xfi 260hr retrofit hydrolic roller cam kit( make sure your heads will suport the lobe lift), decent set of long tube headers, 1 1/2"-1 5/8" tube size, bigger isn't always better, if it's a daily driver.these are assuming under 2500rpm cruising speed.if you want to push the envilope some get a jes knock finder.and the smaller 252hr xfi cam. with aluminume heads the smaller cam will not be a problem.this should put out more power than you have now, with the same if not better milage. giving a real hp guess would require knowing what the flow of your heads will be. and a proper (cpu) tune.keep piston to head quench under .050" this will reduce chances of detonation.i'd get a (cpu) tune done. and if thats not enough power you can always throw nitrouse at it.i would otherwise say an easy 375hp.and a great deal of torgue, where you need it. with a 150hp shot of nos, you'll wreck the hell out of your factory tranny in a quicke hurry.everything in a factory vehicle is designed for a certain amount of power. be prepaired to upgrade your transmission. and good luck.fast/reliable/cheap...pick any 2 out of the 3.
I appreciate the advice. I'll check around with hotrod and carcraft, and see what I find. The biggest concern was the ecu. Didn't know how much trouble that was going to be. I'll start and see where things take me.