In my persuit to rebuild my K5 into a dual purpose buggy, I've begun to think away from the doubler.. and into a stick with a low first gear. I may try and mate up something tricky for a transfer case.. but I'm interested in what other people have done and especially which transfer case they are using (pros-cons). From what I understand the NV450 began production in 1992 in both Dodge and GM 3/4- and 1-ton trucks. Its a cast iron case and weighs about 200lbs. From 1992-95, the GM version of the NV4500 transmission used a 6.34:1 first gear, but after that Dodge and GM versions use a 5.61:1 first gear. All of the NV4500's use either a .73:1 or .74:1 overdrive ratio for easy freeway travel.