I have a 86 GMC K3500 Crew Cab. I just put in a GM heavy duty crate 350 and a Level 10 heavy duty Turbo 400 with a protorque converter. The question is how should I convert to an overdrive trans? A gear vendor is out due to price. I think my options are to either get a 700r4 with the correct output shaft and adapter for the NP205 or find a 700r4 with a 208. I assume I'll have to change driveshafts (I have a D60 front and 14bolt rear, both 4.10). I like the idea of the 700r4 with the 208 becuase I could just swap the whole unit with another truck, but I don't know how much harder that would be? Any ideas would be great! Thanks P.S. Is anyone out there looking for a nice crew cab with only a little rust? Let me know.