Quote Originally Posted by AFSP1211 View Post
They were aluminum 5.3 heads. What engine size they came off of doesn't matter. All that matters is the year they were made. Some early ones had probs with the casting process or some shiz. These should be good.
Not totally true...if they came off an 6.0 ls2 and are stock they would have the sodium filled valves so yes it does matter.