Johnie_West

I bought a set of heads that were from Patriot Performance about 2 1/2 years ago that were sold to me as 5.3L heads. I took them off the car and was inspecting them and found a 4.8 molded in to the casting underneath one of the runners. The casting numbers are ground off smooth. There are two sets of numbers on each end towards the top corners on the exhaust side. There is a notch on the outside edge of each head where there would be a gap between the block and the head. It seems I can remember one year where gm put that notch on the heads but not all years have it. I did a search to find out that the 4.8 and the 5.3 are in fact to the same specs exactly. So now I'm thinking these are 4.8L take off heads that were just ported and polished but how could I find out what year they are?