Except for issue of fit, I would suspect any tach that gets a reading from a negative coil lead and a distributor input would work fine. The diesel tach's circuit is different, which is why it didn't work for your case.

Congrats too for your persistence. I have a ton of completed efforts that I had been initially told "wouldn't work"...

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car