I wish I had known about those mounts, rednate! I installed a 250/th350 in my Dad's '49 3/4 ton. I suspended the engine/tranny in place and built motor mounts and trans mount to fit. Welded them right to the frame. We used a rearend out of a '92 Dodge van, but it was 3/4 ton so won't help you. But the 250 actually has quite a lot of power to move the truck around. Rearend gear is (I think) 3.92-ish.
I'm in the process of doing the same with my '50 and a '65 292. I used the original rubber engine mounts and then fabbed up some pieces to weld to the frame. I'm putting in a NV3500 five-speed with a transfer case for 4-wheel drive so I had to make the crossmember with a piece of 6" well casing in it for the front driveshaft to go through. But then I like to make stuff and have access to the tools. . .
Craig
