head casting #s j or c code

[dmmotes]

Does anybody know what casting numbers there are for J code heads? I have a few sets of heads and am trying to tell if I have any of the bigger valved J coders.

[Dieselboy]

The early heads from around 82 I believe were the only ones to have larger intake valves. The rest of the model years, C or J, were all the same.

[odee]

would you gain anything by putting the bigger valves in a set of heads? What about ant porting work?