The heads on my 70 duster

[abodyfan]

I was wondering if the heads where marked on the 72' engine? So I can tell if I should get a different set of heads, if I replace the block with a date coded 70' 340. I can't see any letters or numbers on the heads. Where are the casting numbers located.

 

[formula_s]

http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Number=4664129&an=0&page=0#Post4664129