Don Know what you mean about the trannys. I had a 41 ford pickup with a 53 merc engine that was wild. It put out probably 180-190HP in a truck that had the bed cut 12" and was channeled 3". Not much weight and she was a mover. Went through 2 tranny and at least the same rears. One night after haviing a few to many beers, I raced a kid that had a 53 chevy with a 265 running 2-4's. I knew I could take him and since I was running open drive shaft for pipes along the side of my cab, it was loud. Well burned about 200' of rubber in first gear and went to shift into second,Bang. Rear end went. Managed to creep home about 10 MPH and parked it. Had alot of fun with that. Wish I never sold it.