If your clutch were slipping you would know it when you take
off from a standstill, or smell it or it would be chattering
when you slip it.

We get so used to hearing our modern engines running at 1800
rpm at highway speeds in our sound proof cocoons that a
stovebolt at 3000 rpm sounds like its gonna fly apart. As I
said, it won't, if it's a healthy engine and not all worn
out.
Remember to, that brand new these only were putting out a
hundred or less HP. Even the modern four cylinder engines are
pumping out a couple hundred horses and the body's are much
more aerodynamic than a barn door, which is what your old
truck is second cousin to.
dg

Denny G
Sandwich, IL