Stephen,

Please read my responses between excerpts of your reply below:

> On Sep 18, 2017, at 4:57 PM, Stephen Eubank wrote:
> 
> ...Somewhere along the line, the speedometer was recalibrated or somehow altered so that it reads exactly twice (and not 8/5) my speed in mph. I've checked this against other cars and radar guns. When it registers 50 km/hr, I'm going 25 mph; 50 mph shows up as 100 km/hr.

If you install an 805 speedometer and use the original faceplate from the KPH speedo, it will read about double the actual speed. That's because the 805 2wd speedometer takes its drive from the left front dust cap vs. Syncros which are driven by a gear at the front differential. The variable ratios that Dennis Haynes referred to were available to correct speedos for when changing R&P ratios.

> So the "puzzle" is: since I don't have a tach, I've used the very-helpful-German shift point markers on the speedometer as a guide (You vill shift now, ja).

Probably not a good idea unless you have confirmed the true speed at those markets via some other means.

> I'm surprised there was that much room for adjustment. Doesn't seem like the difference between 16" and 14" wheels would be hard to handle.

So again, there is no difference between the 16" and 14" Syncro speedometers. If anything, the speedometer drive gears were matched to the R&P which the particular vehicle had as original equipment.

BenT