Are there any differences in the heads from a 4.8 vs the ones on a 5.3? I picked up a set of 862 castings thinking they were 5.3's but today when I was looking them over I noticed they have "4.8" cast into them on the underside. I then looked at a set of 317's I have laying around and they have "6.0" casted on the underside.

 

I thought the only difference was the pistons and crank.

 

I think they use the same heads. I bought some mildly worked heads that were described as 5.3 heads. The cast # they listed was actually for a 4.8 casting. When I asked about this, they said the heads are identical.