The only real way to see if its a Commando engine is by viewing the piston tops. If they are "pop-up" style with 2 valve reliefs and not flattop with 4 reliefs, then you have at least the hi comp pistons. You'll have to take measure the cam to confirm Commando grind or not. The intake/cylinder head mating surface is the same thoughout the 273 years...only the bolt angle and size are different, early to late 273. A late intake will bolt to the early heads if the intake bolt holes are wallered out a bit. Casting numbers will determine if you have early or late heads. A late 64 casting number will be a '65 model year engine, Commando or not.
