Speedometer reading slow

[klinton994]

1971 Mach 1 Speedometer  appears to be reading about 15 mph less than the speed I feel I am going. Below is the set up I have. Anyone have any ideas?

toploader rebuilt by David Kee. 

7 tooth gear inside transmission

16 tooth gear on cable.

3.00 rear end. I rotated tire one revolution and the drive shaft turned three revolutions

27" diameter tires

 

[Don C]

I would make sure your speedometer is actually that far off. You have to remember, these cars aren't as quiet and smooth as modern cars and the noises and vibrations may give you a greater sensation of speed than what your actual speed is. The easiest way to check your actual speed is with GPS.

 

[klinton994]

I will try that when I get it back on the road in a few weeks.  Thanks.