[TonyMadrid]

Thanks for the info but what I am trying to find out without having to tear down the tailshaft is whether the drive gear is a seven or an eight tooth gear. I have tried counting the teeth by placing my little finger in through the speedo gear opening but it is hard to tell.

Someone once told me that Ford didn't start using an eight tooth drive gear until 1980 but he wasn't certain.

It is not a major concern right now as I can try an 18 tooth driven gear and measure my speed against another vehicle's speed (son's car) then work it up or down from there.

But if anyone knows for certain if the drive gear is an eight or seven tooth gear it would make things simpler.