350 w/ 305 heads and TBI intake... help!

[91firechicken]

Hello everyone, let me explain...

I have a 1991 firebird formula that came stock w/ a 305 HO matched with a 700R4 tranny, like most have. I threw a rod through my oil pan making a pretty peek hole in it...

Well, i found a 350 4-bolt main that is a little older... stamped 350 insted of 5.7 and is that light blue that they painted them back in the late 70's. I pulled the heads off of the 350 and swapped them for the stock 305 heads and intake(TBI) that i had from the origional engine along w/ the distrib and coil.

after it was all said and done... primed and timed(4º adv.)... i got her started. She fell on her face when i stepped on the gas... timing was off... i thought. We advanced the timing to 14º, it ran better... idled high around 1800rpm and still loses power when i get on it.

also... i find myself priming it with gas manually from a gas can...


so, i'm looking to get rid of the ECM and go carburated. i have a set of vortec heads for a 350 and a holly 650. would it help if i swap them in? please help!!! thanks for your time!!!

[Trash man]

if u wanted it to work on a tbi chip u woulda needed one out of a 350tbi car most likely, also if u can learn to burn ur own chips u can make more power and get better gas milage then a carb. head on over to team3rdgen.org for info on chip burning

[thenuge876]

I am not sure about this one, but I did not think that the 305 heads were interchangable with the 350. They fit yeah, btu the compression ratios are different and the difference there could help to explain why you arent getting as much power out of your engine. You might want to post the question on 3rdgen.org or wait for some of the other guys to chime in. I looked into doing something like that a while ago and found that the heads could not be changed from a 305 to 350 or vice-versa.