273 commando heads vs. standard

yeah,,,thats why I'm trying to figure out if the heads are the same,,,,thinking of putting the 65 heads on the 66 commando block and runing the dual quad,,I guess I will have to finally pull the 66 heads off and do a side by side comparison,,,,was hoping there were some "experts" on the subject here

Same size combustion chamber. Use the '65 stuff if you want,
it will work fine, just tuning the dual carbs might be a pain.

Can you tell what engine is in my car, by looking at it?? ;)