The rubber valve cover gaskets are also called "neoprene". If you want to order them, tell the parts guy that you have a 66 or 67 273 and you will get the proper fel-pro gaskets. They give the neoprene gaskets for the early 273's because you have to adjust the rocker arms with the solid cam/lifter set up.
Then as stated above, just snug them by hand holding onto the head of the ratchet. Then go back and give one final snug after they are all tight.
