Get a mirror and look on the bottom of the exhaust side for a casting number.
C2242 or C6733 is the standard A head and is unpainted aluminum.
C7707 is the C-type head and is generally painted red in the valley only.
The C head has better porting and generally has a letter C in the valley.
These are the general rules, but if you find a head that varies from these rules, we would love to hear about it.
Restorers have been known to paint a standard head red not knowing or not caring or even intending to deceive…
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