Could someone look for the casting number on their cylinder heads. The casting number would be in the top front corner just outside the rim of the valve cover. It will be a three digit number cast into the head. Depending on the casting it will be on one bank or the other, but not both. Casting # "823" is a U.S. L76 casting. Curious to see if anyone has another part number. Another cast number would indicate a different casting process.

http://i2.photobucket.com/albums/y20/PerthPurplePenguin/car%20parts/L76/P1010129.jpg

Thank you, very interesting.

Thank you, very interesting.

Why?

The 823 heads are the ones that a lot of the LS guys want. With the 823 heads and a mild cam, you are looking at like 425-450 to the wheels with supporting mods. I think the most they have gotten out of them with those heads unported is just over 500 RWHP.

EDIT: Quick search turns out that I believe the 5364 and the 823 heads are either the same for performance or darn close.

The 823 heads are the ones that a lot of the LS guys want. With the 823 heads and a mild cam, you are looking at like 425-450 to the wheels with supporting mods. I think the most they have gotten out of them with those heads unported is just over 500 RWHP.

EDIT: Quick search turns out that I believe the 5364 and the 823 heads are either the same for performance or darn close.

The 823 will consistantly flow better than the 5364, especially on the intake side. While in factory trim there should be little difference between an 823 L76 vs 5363 L76, no more that 10 or so hp in favor of the 823 heads. The better flowing 823 will take better to cam mods or other increased induction mods. Both part types are built to the same specs, the difference is almost but not entirely insignificant. Plus the 823 is cast in Michigan.

Thanks for clearing that up, I'm waaaaaaaaaay behind on this LS stuff.