Is there any difference? I thought that the ZZ4's were the same only without the provisions for the egr. Any truth to this? Thanks.

 

They are the same heads. Neither of them have EGR provision. On the 'vettes that have EGR they use some crazy plumbing to pull the exhaust gas from the exhaust manifolds into the intake. I've got some pictures and flow tables on my website if you wanna know a little more about 'em.

-Mark W.
'88 SC Camaro w/ 305 TBI

 

The L98 Corvette heads, and the ZZ3 heads are the exact same. The ZZ4 heads are the same thing as the L98/ZZ3 heads, except they have the LT4 HOT cam springs on them.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

Whats a good source for the aluminum heads, apart from junkyard corvettes, (none around here) and how much would a set cost?

 

This is where I got mine (I ordered them ported though). They run $700-$800 or so for the pair (I can't check on their price right now, their website seems to be malfunctioning).

-Mark W.
'88 SC Camaro w/ 305 TBI

 

Also try www.salleechevrolet.com and www.paceparts.com

Any GMPP dealer should have these heads.

 

So just so that I have this straight, neither the ZZ4 heads, or the Aluminum L98 heads are emmissions legal? But they will just bolt on? Thanks.

 

They require a special head gasket and I think a special set of head bolts if I remember correctly. You can get both of these items from any GMPP dealer as well.

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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."