Mechanical to Electric Impulse Tacho Conversion

[Riley]

I wish to exchange the mechanical guts of 3" cable-driven, vintage RPM instrument with 'impulse-activated' innards salvaged from a modern electronic tacho. A google search tells me, with careful procedures (no instructions) this a relatively straight-forward conversion however I've got 10 thumbs and no cojones so am not game to try it. Can anyone steer me towards a technician/service who might do the deed? The current black plastic tacho with red-painted wide needle just doesn't look the part in the Pietenpol. Tks in anticipation. Riley