I am currently in much the same situation. I have a 51, 1.5 ton flat bed with hoist that I am restoring. After much consideration, I am installing a new 261 motor with the existing drive train. I am lucky in that the truck has an original option of the 5.43 rear end. The truck could reach 60 miles/hr with that gear ratio, with the orignal 216 straining a bit. I am ok with the speed of 60 miles/hr but the power of the 216 and low pressure oiler was going to be a problem. Everyone, and I mean everyone has stated that a newer high pressure engine must be installed if you want to really use the vehicle. You are risking the 216 engine at any highway speeds above 55 miles/hr and that is with the 5.43 gear. If the truck has the 6.17, then you are in more trouble. I will live with the 5.43, and 60 miles/hr with the newer 261 engine. At least I know I can drive it on the highway but maintain much of the original look.
Good Luck
51flatbedchev
