My buddy has a set of ZZ4 heads that he'll give me for my car but I have an 89 Pontiac Formula 350 TPI. I wanted to know if my stock lower manifold will bolt up to the ZZ4 heads.

 

They are the same heads that GM used on the 350 TPI engines from the Corvette. They will work just fine on your motor.

 

You will need the lower intake from a corvette and the EGR tube to weld into the passenger side header. The L98 heads are sans EGR passages and use the old style intake bolt pattern. You could make the L98 F-body intake work by elongating the 4 center bolt holes with a dremel and reprograming the computer to eliminate the EGR.

 

I thought that the late model lower manifolds were all the same (89 + up). I was hopping that I wouldn't need to hunt down a manifold, I would just be able to bolt the heads on and rock and roll.

 

That only applies to 3rd gens. Vettes don't count.

 

Yea. I think it had something to do with them being affraid the strange angle of the center bolts would warp the aluminum, or strip out the holes easier, etc.

I'm sure they had a legit. reason. They always think they do.

 

So far you guys have been helpfull, but I am looking for alot more input on these heads and my lower manifold. I am trying to make them work for Street Car Chaos at US 41. Anymore input would be freakin awesome.

 

Fast355 told you what you have to do.

Yours are iron and weigh more, and they flow about the same as the ZZ4 heads. So you'll be doing a couple of mods to make them work all for saving ~40 lbs. Is that worth it to you?

 

I should have mentioned that I am not running any type of emissions no my car, no cat, egr tubes, air pump. I don't think I need to worry about the egr tube. The ZZ4 heads are not just lighter than my L98 they flow more also, and have screw in studs, and better springs. But okay, if you guys say all I have to really do is oval out the 4 center bolts than cool. The bolt pattern is a vortec on these ZZ4 heads are they, cause then I need to change the angle of the bolts.

 

The Vortec pattern is completely different - different port position, different bolt position, different # of bolts, etc.

The ZZ4's are the same pattern that was used from 1955 to 1986. The only thing that changed in 1987 was the angle of the center two bolt holes on each side of the intake, and only on iron heads.

 

You're right. They do flow better on the exhaust side. I forgot about that.

And they do have screw in studs, but those aren't guide plates as we know them. Those are used for production/assembly line reasons. Self aligning rockers are still needed.

12499712 -ZZ4- 350H.P. Turn Key Crate Engine Package - 12499712

Just so you know.