I think it'll screw in but it may not work. It may even cause things to bind up and possibly ruin the switch. Mopar changed rooster combs a few times and I think the 65 is different than a 70, although that's just going from memory which isn't the best. Why don't you just leave the 3 prong in it and hook the wire to the middle terminal? The middle terminal on a 3 prong switch is the same as the single prong on the old switch. My 68 originally used a single prong switch but rather than pay $100 for a NOS switch I found a pigtail off a newer 3 prong switch and used just the center wire.