My 67 Tempest has a peg leg 2:56 RE. I have an utterly rusty scrap 1964 Chevy Elcamino w a 283 3spd manual out at the yard that has the RE in it. All the RE's in that year were three series as far as I can find out. Will these RE's swap out? No matter that it has or has not a posi tho I'd like a posi. Its the fact that a three series even the lowest numerical one (3:08) is more attractive that that 2:56 RE. If its slightly narrower that would be even more attractive. (wider rubber )