My 39 Dodge pickup is the same cab as Couper's cab.
I'm 6'1" and 270lbs. I built the truck because I loved the body style, but after it was built and I could drive it, I discovered I could only drive it for about an hour and had to get out of it. Even with the seats on 6" high pedestals and the seat back against the back of the cab, under the rear window frame, my knees were on each side of the steering wheel. I think the biggest problem was the angle at which me feet had to bend to operate the gas and brake pedal. I had the seat higher, and lower, but the position I ended up at was the best bet. I drive my stuff, so I spend a lot of time with seat and pedal placement. The cab was just too small for me. The seats were the 2nd row buckets out of a 2000 something Chrysler mini van.
My wife that is 5'4" tall loved driving the truck. I managed to sell it and get most of my money out of it.