Thanks for the reply! Sorry I should have given more info, my 273 does have the domed pistons with 2 valve reliefs, I wasn't aware of the Holley carb part of the equation. Good to know!
That is a 4 barrel piston and standard bore. (3.625) 67 was the last year for the Commando (Plymouth) and Charger (Dodge). Both were the same between brands just a different sticker on the air cleaner.
