1970-Bronze

Ok, maybe this is a silly question, but can I run cast iron exhaust manifolds on aluminum heads?

Trying to work my budget....and I have a cracked head. Headers are on the list later this year.

Corey_68

I guess if you really wanted. :jester

Jughead

Didn't the L-88's have aluminum heads and cast iron manifolds from the factory? :D

Gordonm

Don't forget the few L89 motors also came this way.
Also ZL1 motors came with them.

Shark Racer

Only if you extrude hone then and then fill the primaries with helium.

-Steve :jester

L79vette

OK, lots of fun being had here.

Yes, you can. It won't work any worse than it did on the iron heads, if...
the inlets to the manifolds don't block the exhaust ports in the heads.

Hold the exhaust gasket that fits the manifolds up against the new heads. If the ports are blocked at all, port the manifold openings. You should be able to open them up with a die grinder. It probably won't be necessary, though, unless you are getting some special race heads with unusual exhaust ports, or the late model D-port heads. Some heads may have ports different enough from the stockers that you can't open the manifold up enough. These heads may also want spendy headers too. What heads are you getting?

Since you are going to all the expense and trouble of changing out the heads, adding headers to the deal is not really expensive or time consuming in comparison. You're already going to have everything apart.

1970-Bronze

Aluminum TrickFlow's.

jamesx0

Um...Both the L89 and the L88/ZL1 intake manifolds were aluminum. Aluminum head vettes have only ever come with either an aluminum or a composite (LS1) intake from the factory.

L79vette

He's talking exhaust manifolds.

Trick Flow should be able to tell you the port shape and whether it's any different from stock Chevy heads. I doubt if it is, those are not real exotic parts.

Smokehouse69

I used stock cast iron on my ZZ-4 with aluminum L98 heads. I carefully checked the alignment of the old exhaust manifolds with the ports on the heads, and opened them up so that they match the ports on the heads.
It took a while and a couple of stones for my die grinder, then I only used high temp silicone between the the heads and the manifolds.
I've had them on there about 18 months and 6k miles and have not had any leaks.
Original cast iron manifold to heads did not use any gaskets, so I didn't put any in.

comp

if mine i'd wait and save for headers, the iron is going to choke those heads

Fevre

Ran them with trick flows with not problems, LT1's use the rams horns and they do flow well just not as good as headers.