i've got a 91' lo3 305 that i've parked until i swap the fuel pump. i've built engines in my younger days, so i'm not entirely new to them, but this fuel injection is a different ballgame.
i've read the different post considering the build-up of a 305 and everyone has thier own agenda.
now my question is which heads will bolt to this 91' 305 block? use to be you could interchange all the sbc parts, now i'm being told that the older heads will not bolt up to the newer blocks and viceversa. which is correct?
thanks,
roy

 

The older heads will bolt to your block. If the heads are old enough, your accessories won't bolt to older heads, though.

The other changes were in the intake manifold bolt angles (center two on each side only) and center-bolt valve covers. Both are kind of nice to have.

The heads that will work and are better than what you've got are 1987-up 081 (305 TPI and 1987-only LG4) and 083 (L98 350's). The latter are 64cc chamber, so if you use them, you'll need to shave them down about .040". I assume you know what else is required if you do that. The 081 will have the same 1.84/1.50" valves that you've got now, but 1.94" intakes are fairly simple to put in. With basic porting, either will make very nice performance heads.

The other alternative is World Products S/R Torquer 305 heads. They are available with the proper bolt patterns, have the 1.94/1.50" valves, but do benefit from the basic porting routine.

 

The 081s are the best ones as far as direct bolt-up to that motor. They have the correct valve cover and intake bolt pattern.

They also come on L69 motors, which is used in Monte Carlo SS.

Anything to do with any kind of TBI should be avoided.

 

i take it that the 081's also use the centerbolt valve covers? i'd like to get away from those if possible, that way i have more options to dress it up a bit, but its not that big of a deal. thanks

 

You could also use 416 heads; basically the same thing, except with the early-model intake bolt angle and perimeter bolt VCs

 

Roy,

I have done the head change you are talking about. I also have the LO3 and went with the 416 heads. If I had it to do again I would go with the 081 heads. The center bolt/perimiter bolt is not that big of a deal. You can get valve covers for center bolt just about anywhere these days. But the center bolt holes on the stock intake (to fit the 416's) was a bit of a pain. It was not hard but the center bolt valve covers would have been less of a hassle.

If I want to change intakes I have to either do the enlongating and reaming out the bolt holes again or get an intake that will fit the bolt pattern on the heads and then go the route of the TBI adapter plate and then lengthening the throttle cable and cruise control cable..etc.

So in retrospect, I think the 081 and centerbolt valve covers would have been less hassle.

But both will work fine for your application.

 

Having had both (and many more of the perimeter), I'll take the center bolt any time I have the chance.