273 super commando #4 and #6 not firing

plymouthvaliant said
Thanks everyone. When I pull the new wires one by one from the new plugs #4 and #6 do not make any difference in the way the motor sounds. When I pull any of the other wires the motor sound like $hit. I am waiting on a compression gauge to check the heads. I don't understand how the motor could sound pretty good without two cylinders firing.

Shiiii, I drove my 273 4bbl "S" home on 5 cylinders and That was on the freeway! Im guessing head gasket too, as you know: no compression means no fire in the hole. Blown gasket may show bubbles in the radiator or some serious blow by in the crankcase.