On the later models the exhaust went under the frame rail before the skid plate, along the outside of the frame rail, and then back under the frame rail after the skid plate. It continues over the rear axle and the across the back, where the muffler is located, to exit on the right side.
Nice! I have all that fuel injection stuff, but would have to alter it a bit to make it work,so it won't be going on there.It still runs, dispite all the times it should have blown up.
I ran a turbocharged 350 in a '74 40 for a while. Don't know the exact hp numbers, but it was up there. Stock drivetrain with 33x12.50 tires. I didn't break anything. Maybe I didn't try hard enough.