The 283 has good torque for a little V8, mine still has the Rochester 2G carburetor with the original vacuum-mechanical governor. The shop manual says 4000 rpm is governed speed and is adjustable, I have it set at 4000. When I acquired my truck it ran very poorly, I pulled the engine and tranny 'cuz the clutch was trashed and in the process I removed all of the tin and intake manifold from the engine, cleaned it up internally, replaced the wiped-out cam and lifters with a cam I had on hand from a previous build. All new seals and gaskets. New clutch, resurfaced the flywheel, normal tune-up procedure, truck runs well. Mine had a single speed rear gear, through the great help of a fellow Big Bolt member, I was able to put a 2 speed pig in it, now has 6.80:1/8.10:1 rear. With 8 forward gears I can easily match the road speed to the load. I have 10R-22.5 drive tires that are roughly 41 inches tall, truck will run at 60 - 62 mph at governed rpm. I think a 350 would be very adequate for your truck and intended use, I have a 383 that I built for my Vette but decided not to detract from its originality, so if needed, I can swap in the stroker motor in place of the 283. I know a lot of folks are tired of the old-style small block Chevy motors, but you can't beat them for dependability, simplicity, economical build price, extreme parts availability, etc.
