Hey Jim, there's no clearance problems putting in the original style 10.5/1 pistons into your 273! That's what they did at the factory, and I understand that Egge makes the replacement pistons! Incidentally, all 273 motors were solid lifter! Now, with the domed pistons you'll also want to "bump" up the cam to commando specs or comparable also to take advantage of that compression! Good luck and have fun with the build!! Geof
