I believe the "late" block began with 74. The casting numbers are different. Regardless, I wouldn't trust QC from the 70's and would have everything sonic checked for core shift, etc., before going crazy with one.
Agreed & I think the first number went from a (3) to a (4).
mine was cast 10/10/73.. 496 block. What do you mean 3 to a 4?
When it takes more than a sweet mullet to prove you rule at the trailer park..
