Heavy hauler mpg's and highway speeds?

[MjrBummer]

Hey everyone,

I've been looking through a lot of the threads, and I see there are quite a few very talented wrenchers on here.

I was curious about some of the heavy hauler projects though. The C50/C60's for example. I see a lot of them being shortened and getting pickup truck boxes put on them. What kind of highway speeds are you able to achieve with them and what kind of mpg's ar you guys getting? What kind of engine, carb, tranny, rear end gears are you running, etc.

Is there a preferred engine and carb setup people are running? Just looking for opinions on horsepower vs. torque and such. How many are running diesels?

I know, a lot of questions. That happens with ADHD.

I have a 1967 C50 School bus converted into an RV. GVW is 19,500 lbs. I'm running a 327, a 1965 so my Dad says, and a 4-speed w/split rear. The engine is real close to the firewall and I won't be able to get in to see if I can get at the casting numbers until spring when the ground is thawed and dry to find out for sure. I have no clue about the rear gear ration yet.

Any good links to manuals for the brakes, etc.?

Thanks in advance for any input.
Bill