Thanks to everyone for the replies. NM51: I don't think I need worry about going too fast. This is a 53 model 6400 Stock truck. The only way I would ever get to 80 would be to drive off a cliff.
I think Tiny probably has the answer. I may be wrong, and probably am, but it acts like it just need some lubrication. It tries to register, but seems sluggish. The truck is over 50 years, and didn't move for almost 25 years before I got it, so it seems logical that what ever lubrication it ever had is dried up.
It will be a little while before I get to the speedo. I have other more pressing things to work on first, but will let you know how all this comes out.
Thanks again for all the information. Allen
