Some guys really get nervous about high speeds in an old truck. I had a 350 engine in my '53 3/4 ton, everything else stock (except the pumpkin which I swapped for a 4.10). Had it up to about 85 several times on the highway. Bouncy, rattley, but not too scary. Recently put a '54 235 engine in, still can do 65 fairly comfortably. My advice: find a later 235 (54-62) or 261, (got my 235, running, for $300) do the pumpkin swap (paid $250 for my 4.10 pumpkin out of a '72 Chevy van). More power and speed, but still a stovebolt.
