I have a 91 firebird 305 tbi. Anyone know what cc the cylinder heads are on this engine? Looking into getting new ones (performance) and wanted to get the right ones. Thanks

 

I believe stock 305 heads are 58cc. You could get a set of vortec heads, which are 64cc and have them milled to retain compression. You'd need a different intake manifold for vortec's though.

My advice would be to build a 350 for performance on an engine stand while you can still drive your car as is daily.

 

Yeah that's kind of what I was beginning to think. Every which way i've looked at it it was about the same price or a bit cheaper to build a 350 for it. I've thought about doing that using the existing tbi setup. But also thought a carburetor would be easier. Still looking into it. My 305 is running smooth right now so I have some time to figure it out.

 

I wouldn't waste time on heads purchase for a 305, unless you get a pair for under $500 - then we're still talking custom chip tuning unless you swap to carb. Either do a 350 TBI swap, or carb a 350 and swap it - the 305 just isn't worth the time/money/trouble to me.

 

that's prety much what I've been leaning towards. When I looked up the price of a stock replacement 305 from autozone and then a stock 350 (that would have come out of a car like mine only a t/a) the 350 was actually cheaper. If the reman company built the 350 to spec then it would have 245hp out of the crate. Compared to the 170hp of the 305.