Thank you guys SO much for the replies and suggestions - very helpful.
Sounds like it might be expensive and possibly difficult parts to find

Besides - this truck is so nice and original - I hate to change it out ...guess I am a purist at heart. Put up with the low gearing of my 1955 MG for 40 years now - just stayed away from major highways as 55 mph is over 4,000 RPM in her.
I hate to pass up such a great truck just because of this ... do all of the early - mid 50's Chevy trucks have the granny gearing?