My son's 1946 2 ton, first year 235 was available
did 53 empty on a level section of the interstate for
a brief test to see what she would do.
For the first year doing his catering business he would
do 42 - 45. Of course he would lose speed going up
grades and when the down grade was steep enough
he would let the truck go past 45 with his foot off the
gas pedal when road and traffic made it safe.
Then he had a 1954 235 rebuilt and put in near the end
of last catering season. 19 more HP and 8 lb more torque.
Accelerates a little better. He can get away without using
1st gear on level pavement but prefers to still use 1st
gear all the time to be easier on the clutch.
From following him he now loses speed a little slower
on the grades and I have seen him hit 46 -48 on level
grades on his way back to "he barn" after he is returning
from doing a catering event. His truck is never empty
anymore.
I'll have to ask him if he tested his new top speed yet.