ENGINE MILES?

Looks like it says "miles" to me, not hours

 

It would have to be hours if it's on the tacho but why it says miles has got me beat. Besides, there aren't enough digits on there for it to be miles.

 

I was thinking the same thing, but it does not look like a modern tachometer. I thought perhaps a few decades ago that was the standard number....I mean 99999 hours seems like an awful lot

 

Maybe its the predecessor to the modern hour meter. My guess is that the modern meter is more like a quartz watch...ticking away hours at a constant rate as long as it is recieving power. Your gauge may be mechanical, adding hours, or in this case "motor miles", faster as the RPMs go higher. The curious kid in me would want to take it apart and look inside.

 

It makes sense. At 2370 hours it would have averaged over 100 MPH. With 10704 hours it's more like 22 MPH.

 

Now that I think about it, 10k+ seems likely. If it's a farm truck, figure at least 12 hours on days it was used. Over the course of nearly 50 years, I'd say it's had at least 1000 days of use, that's about 3 years of usage on a normal truck.