What spark plugs to use?

autolite 65 what I run strong and dependable, but I run a hot Factory X headed 345 never a problem .
Thanks K.O. I hand started the plugs but my regular spark plug socket wouldn't go into the hole to tighten them?? Do the RHS LA-X heads need plugs for Magnum heads? I had to buy Magnum head bolts since the LA bolts where too short, except for the longer one on each side.