The 1/2 ton truck uses the same engine and rear axle (ratio) as a Master passenger car (4.11).
I drove my Master car at 55 MPH for long distances on the inter-state highways. Often ran at 60 MPH for shorter distances also. The only modification was I installed aluminum pistons to decrease the load on the rod bearings.
The truck could do the same but 55 MPH in a rough riding truck with not firewall pad, a small enclosed cab and no cloth upholstery to soak-up the noises will sound very stressed at 55 MPH. Most feel about 45 is a comfortable speed.
With the light weight and the 207 engine power will be better than a car below 60 MPH, where wind resistance takes over.
The car and truck brakes are the same and when working properly are adaquate.