Welcom Mr. Ductape,
I'm trying to picture the 39. I have a 46 1 ton panel that required lengthening of the S10 longbed frame. I bought the 46 as a rough project that the previous owner started with a '78 full size 3/4 ton chev C/K frame. The full size frame's tires stuck out too far for my tastes, so I went to the S10. Using an inexpensive S10 donor, one fairly big swap nets you much newer tech brakes, steering, suspension, etc. And the aftermarket support for S10s is very strong. The 46 is narrow at the front of the engine bay when compared to later trucks. The engine location of the S10 was about a foot too far forward for the 46 truck body. I had to swap from a 2wd rear end to a 4wd rear to gain 4 more inches in width because the tires were rubbing on the inside of the wheel wells. My 1-ton has a longer wheelbase than lighter duty trucks. I think *you* can use the s10 long-bed frame without cutting. After putting an S10 frame under an old truck, I'm sold. It's no small job, but niether is setting out to upgrade the rearend, brakes, steering and engine. See the truck project in my tagline. Oh, we need peeektures!! All the best - Mike