I saw a couple of transmissions at the yard yesterday that seem to work. First off, what is the spline count for the imput and output shaft of this gear box? Also, is there a transmission that was used on GM vehicles that may be confused with the SM420 during the same era? Why is there no SM420 marks on the casting. I found some with 390 and Pinheads begins with 381. However, the SM465 has a 465 on it. One gear box in particular that came out of a Chevy Apache had a drum brake assembly on the rear and a funny shifter looking thing on the passenger side. I am not sure if it actuated the drumb brake. Would one of these transmissions work. Also there was one that had a frozen imput shaft bearing It probably has considerable rust in it as well. Should I just stay away from it all together? Thanks Pablo By the way, I found a pretty stripped down FJ-55 there if anyone needs anything.