Virg,
This must be a stomp starter on your old truck, right! The starter can be fine electrically, but the starter drive can be busted mechanically.
If your linkage is tight enough to cause the starter switch to make contact, the mechanicals are probably engaging the starter drive to ring gear. The fly in the ointment would be the little internal clutch in the drive itself. This is most likely gunny-bagged.
A new starter drive would probably cure the problem.
Stuart
