Heres what i got going im putting a 383 in my 1966 D200 with hydraulic bellhousing.The tranny in the truck says its a 4 syn np 435 i believe it has the 4 to 1 gear for first.The other tranny i have is out of a D500 which has the 6 to 1 first gear it also has the 1 3/8 input shaft with 10 spline.It also has a pto mounted on it.Im leaning on the D500 tranny it looks to have the larger u joint and has the park brake mounted to it.Can the rear yoke be changed between the two or do i have to find a special yoke.I think in my mind having the larger input would be a stronger tranny but this is all new for me ran automatics in most of my sweptlines other then a couple three on the tree six cylinders.The truck has a slant six with 50000 original miles the tranny and motor runs great but im into the big blocks.The tranny i believe in the truck would be more of a hassle to drive having to use all 4 gears when not loaded.