The tach shops will run a new or rebuilt tack up to any number you want....
for about the price of a hobbs meter. But I doubt if I'll find a dual
recording tach.
Jim

If you find a dual recording tach it still will not tell you the hours on
"your" engines, you will still need to do the math. I would go with the
less
mechanically complex tach and a Hobbs meter. Hobbs meters are cheap and
you
could put in a "0" time one at the next engine overhaul so the times
matched.

Allen