red58, you might be onto something with the speedo. i put a slightly taller tire (215/85.16) on it lately and that of course adds weight and makes the speedo under-register a bit. maybe it all just adds up or subtracts, whichever way you want to look at it!
thanks much for everyone's help.
tony

Overland Blue, 1953 GMC 1/2T, 100-22, 228/1bbl, 4sp/4.10 6v, shortbed/fender side/5-window.