adrian rocs

ok i recentlly bought a 85 z28. it has the 305 tpi engine in it stock. i have a rebuilt tbi 5.7l engine from a 88 silverado 2500 just sitting in the back of my shop. are the blocks pretty much interchangeable? can i throw my tpi stuff on the tbi block? if i can do you have any other suggestions as far as keeping the heads or swapping them also. any idea of what kind of hp/tq gain this upgrade in displacement might give me?
thanks in advance for your help.

alpine247

yep u can throw ur tpi set up on the 350 but u need to switch the injectors to run that 350 properly..

adrian rocs

ok i figured they were identical. should i keep the 350 heads or swap the 305 heads on the block as well? any thing else you would suggest other than upgrading my injectors?
thanks for your time and answering my questions.

alpine247

keep the 350 heads if it was me i go ahead a port the intake base and plenum and heads.dont do like me rebuild an engine had all the stuff off and didnt port anything now it all back together in the car and i wish thousand times i did...

adrian rocs

yeah i had planned on some port work.
thanks for the answers.

Darkshot

iTrader: (4)

Hold up. Get the casting numbers off the 350 TBI heads. Good chance they are 193 swirl port casting. I'm pretty sure your 305TPI has 416 heads (double check to be sure).

If you do a search on 416 heads, I think you will find they are far superior than 193 heads especially when you do some work on them (larger valves and a port job seems to be what people do).

Might want to invest a little bit into the 305 heads and use them combined with the TPI on the 350 for best performance. Do a little bit of research by using the search on these forums and decide for yourself.

Depending on the cam you choose you might be around 350TQ and 250HP with this setup. Thats just a guess though, figuring that the motor would be similar or maybe a little bit better than a stock L98 (with bolt ons). Headers and 3" exhaust will let the new engine breathe and give you even more power.

adrian rocs

ok ill check out the casting numbers on the 350 when i get to my shop today. im actually thinking about rebuilding the 350 again and adding some forged internals since it was rebuilt with all oem parts. i figured now would be the best time to do that since its just laying there and my 305 is still in my car and it runs and drives.
thanks guys.
im open to hear anymore advice.

adrian rocs

hey darkshot im from the modesto central valley area, pretty cool to see some one from the smog state california, alot of people seem to be out of the state.