57 Tach

[Tony P.]

I changed my 57 to an alternator and now Im using a tach driven distributor. Now my tach is not reading properly. Im wondering if anyone can re calerbrate the tach to go with the distributor. I want to keep the dash stock appearing so a tach on the column is not an option.

[Bruce B.]

Re: 57 Tach

Tony,

A tach drive distributor turns at 1/2 the speed of a tach drive generator therefore you will have low readings on the tach, actually 1/2 the actual RPMs.

[John H.]

Re: 57 Tach

Any of the usual instrument specialists can rebuild/recalibrate the tach head to read twice cable speed (from the distributor) instead of full cable speed (from the generator gearbox); the tach came both ways originally, depending on the engine application. I'm sure Brian Tilles (Corvette Specialties of Maryland-West) can do it.