A standard non overdrive transmission of that era uses a 20 tooth steel speedometer gear and the standard rear end ratio is 3.90:1.
There may be a 19 tooth gear available. I would have look through my collection to be sure. Car transmissions and
the overdrive versions use a plastic gear so there are more selections available. Cleaning and lubing the speedometer head
could make a big difference. It's also possible that it may require a ratio adapter because of the tire size.
Fred
Note: The 21, 22, and 25 tooth plastic gears used in OD units and cars will not work in a truck
because the drive gear is a different size.
Going with the above earlier post of a 20 tooth steel gear (assuming driven gear but others can clear this up)
Then that would mean you need a 9.4 drive gear. which is not a valid value.
if your drive gear is a 9 then you need a 19 gear driven side.
so we need to know number of teeth on drive gear.
If anyone knows what the stock drive gear teeth are that would be outstanding.
