Gm BBC Heads 396 question
I picked up an untouched 4-bolt 396 block today that came with a pair of oval-port heads, GM castings 3964290 and 3917215.
From what I understand, one of these castings was a later service replacement installed around 1974. Both heads now appear to have the same valve sizes (2.190"/1.880"). Originally they differed in valve sizing, but that seems to have been corrected at some point.
Am I correct in thinking that, as they sit now, these two castings are effectively the same in terms of functionality?
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