Tach's for 34' Californian

[Stu-L]

My Californian has twin Perkins 4-236 with mechanical tachs. The upper and lower station tachs are in series with the sending unit on the engine. I would like to convert to tachs that are driven by the alternator.
Question: Are the upper and lower tachs wired in series and then connected to the alternator tach output?

Any one changed to alternator driven tachs?

 

[FlyWright]

Both my lower helm and FB tachs are alternator driven. The alt sense wire goes to the lower helm tach, then continues to the FB tach...series. I recently changed the stbd alternator to an externally regulated Balmar. I only connected one wire for the tach drive and both tachs picked up the signal.

I also have the 4.236.