So I am rebuilding a 305 for my 86 Camaro and I've got a few questions, as well as a few options. Right now, I've got a pile of parts that I payed bottom $$ for but I'm wanting to get the best performance possible (I'm weird like that I know). I've basically got 2 blocks; one TBI and one TPI. My first question is why are the bolt patterns on the two valve covers different? Is there a preferred choice between the two?

Also I may be able to get my hands on a set of vortec heads, what exactly makes these better? And then how will that effect my decision about what to do about injection? (Tune port, TB, carbeurator).

Sorry for my ignorance, thanks so much for ya'lls help.

 

well they are obviouslt two different year blocks, in 87 they went to center bolt heads, those vortecs are gonna be center bolt heads, vortecs with tpi can get you pretty good power with the right cam.

 

The Vortec heads are considered by many as one of the best cast iron small block heads that GM put out. They're just great flowing heads. 305 heads are doggy by comparison. Especially the TBI heads which were designed for low rpm grunt and gas mileage, not for a heavy breathing, high winding engine.