Does anyone know how to tell if you have type 1,2,3 or 4 12-bolt rear end? I want to put a larger ratio in but can't proceed until I know whether it will fit. I came across this in the most recent Hemmings Motor News, and it said that type 1 rear ends cannot have anything higher than 2.73. I don't have the article in front of me and that's all I remember. My current setup is a 12 bolt with a 2.73:1 with a TH350. Any help is appreciated.