A 4 horse trailer is going to need a bigger truck than your 3600 to haul (and stop) it safely, regardless of what frame it happens to be on. That's dual rear wheel, 10,000 pound GVW territory, probably with a gooseneck hitch in the bed of the truck. The current 3600 frame and suspension will probably handle a 2 horse bumper pull rig with a good set of trailer brakes, with a V8 conversion and some brake upgrades to the truck. I'd suggest using something like a mid-1970s Cadillac 472 or 500 engine and a Turbo 400 transmission, but I'm an old geezer who's stuck in the late 20th. Century! Some of the young sprouts will be onboard with some variety of LS engine, an overdrive trans, and half a dozen computers. Have fun!
Jerry
