A friend of mine cracked a head on his 85 IROC w/ a 305 TPI. What's the difference between the 85-86 heads and 87 and up? Would 87 and newer heads be a direct swap? Are there any other heads he can use in a direct swap? He doesn't have much $, so he's not going to be looking into vortecs or anything. Thanks for any info.
Rob

 

The difference between the year models is the intake bolt holes and valve cover bolt arrangement.

He should get a head from a 87-92 305 TPI, or a 87 Monte Carlo with the L69, or a 87 LG4. It should come from those applications ONLY. He needs to look for casting number 081. Under no circumstances should he get any other casting, from any other application; above all, he should avoid the 305 TBI heads.

There are no other heads that are a direct swap, and which will preserve the way his engine runs. Any other head casting will drastically downgrade his engine.

 

Check out World Castings they have a 305 head that will give good performance at a good price.

 

But his engine is a 1985 model, so shouldn't he try for the 416s?

601s would also work fine, assuming he really has an 85 model.

 

Ooooops, yes your'e right.... I jumped directly to the 87 comment and outsmarted myself...

 

Not a problem. After all the solid, valuable advice you've provided, an "OOPS!" or two is understandable. I've made the mistake of skimming the text and missing key points much too often, but I just keep on screwing up...

You can successfully use 1401416, 1401440, or 14022601, castings with no compression loss, and no real concerns about port flows. If you don't mind spotting and drilling/tapping the accessory holes in the ends of the heads, you can also use the older 3782461 or 3782461X castings (if you can still find them), but the newer castings will flow just as well or better with a little port cleanup.

If your friends doesn't need the car ASAP, a little time spent cleaning up the ports would provide some real benefits. Sitting Bull has a reasonable guide that might help out. In any event, you'll want to at least recondition and crack check the heads before intalling them.

You could also use any of the heads RB suggested if you have the time to do a little bolt hole alignment on the intake and install guide plates and screwed rocker studs.

 

thanks for all the info