Do the aluminum L98 heads have positive type valve seals or is it the ZZ4 or is it both?
I am trying to identify the heads I picked up to see if they are actually ZZ4's or L98. I am curious if I need to upgrade the springs or if they already have the better ones.

 

From my understanding, the factory Corvette '113 heads had standard valve springs along with oil slash shields. Not sure about the valve stem seals.

The ZZ4 heads were supposed to be the same as the over the counter GM Performance Parts aluminum '113 heads. These heads have the orange colored Chrome Silicon valve springs along with the light weight retainers, no splash shields. They have positive seals on the intakes and umbrellas on the exhaust.

RBob.

 

Thanks RBob,

I am going to say I have the ZZ4's. I have poitive seals on the intakes and umbrellas on the exhaust. I have no splash shields just retainers. The springs seem to have blue paint on them though?

 

I thought I remeber hearing the ZZ4 heads have hollow lighter valves as well as the above mentioned.

 

Yeah I heard something about sodium filled ex valves, but I don't think mine are. I was actually thinking of replacing the valves with some swirl polished undercut ones.