[Benson]

FWIW:

Before you spend too much time on this I would try an old Analog meter.


I still have a Simpson Model 260 I got in late 50s.


In the late 70's every time I tried the Company Fluke Model 8020A ( late 70's meter) on a running engine it did not work well ... too much electrical noise from Model A ignition or generator.


I have not tried the Fluke 77 to see if they shielded that one better.

I might try that this weekend!