Quote Originally Posted by Frenchy View Post
Not if they're all the same casting number. 799/243's are the same no matter what engine they come off of. 5.3, 5.7, 6.0 have all used 243/799 heads at some point, and they're all the same.
Like I said above the only difference would be if they came off a true LS2 from the car....then they would have the sodium filled valves. But other than that they are the exact same heads that come on the 4.8,5.3,and the 6.0 in all GM's cars and trucks.