In my searches I`ve run across several threads that talk about the newer 113 castings may be better than the older ones or the ones off the zz4 may be a revised version with some decent work done to them.I bought mine new from pace gmpp in late 05 early 06.I hears they changed a couple years before that.I`m trying to figure out if I may have gotten the better ones.We just put them on without paying much attention and I honestly wouldnt have known what to look for.I really dont want to pull the intake and heads just to find out.The part number for the ones I got is the same one for the heads that come with the zz4 engine which is supposedly the heads to get,but some of the post are saying they ordered the 463`s and some are saying they ordered the 113`s.I know they are basically the same head but the revised/worked over version is supposedly flowing way better than the heads that came on the corvette L98.Thanks for any help.

 

The casting number is under the valve cover. You don't need to remove the intake and heads to find it.

 

Sorry,guess I wasnt clear.I know where the casting number is and I know mine are the 113`s.I`m just wondering if my heads might have the work to them I`ve heard.I think Fast355 said he got some 113`s with some work already done to them.And A guy on the tbi sticky sid he got some 463`s with some work done to them.All from gmppI guess when I swap my intake I`ll have to pull the heads and take a look.

 

The ZZ3 heads and Corvette L98 heads are 100% identical. The ZZ4 heads have upgraded springs in them, the same ones offered in the LT4 hot cam kit. Otherwise, they are the same casting as the ZZ3/L98 heads. I have never heard of a different casting, only the difference in the springs.

 

Not entirely true. They also had to open up the retainer-to-guide seal clearance distance on the ZZ4 crate motors. True production line factory Vette heads the retainer will hit the guide seal around .480" lift which is nowhere near enough for the .525" lift on the exhaust side of the ZZ4 cam.

Beyond opening that distance up and installing better springs I don't know if there are any other differences. I seem to recall someone posting a while back that there were valve/valve seat/port improvements as well, but I don't have any personal experience with that part of the head myself.

 

113 alum L98 head (WOW!!! GMPP Aluminum Vette Heads): 243 intake; 192 exh (slightly ported by owner, GMPP pn 12556463)This is one of the posts I`ve found that I`m refering to.Fast355 has one that is similar.I`ll have to see if Ican find it again.
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Try again.link didnt work.It`s in the tbi board sticky head flow data.https://www.thirdgen.org/techbb2/sho...hreadid=236508

 

https://www.thirdgen.org/forums/afte...305-heads.html

try this link as well.They start talking about this in more detail around post number 35 or so down to post 39.

 

ttt

 

Anybody read the links above and get anything from it?Maybe they got lucky?Maybe all those heads form like 2002 up got it?

 

Nobody wants to take a stab or offer any suggestions.