58 tach 270 hp vs. 290 hp Question

[John S.]

I have a 58 tach that has the reading of 8000 RPM and has no rev, counter. I new that this tach was used on the 290 hp fuel car but did not know that it was also used on the 270 hp car. Were both of these tach's internally the same or were they different, since one ran off the gen. and the other on the dist, If they are different is there any way you can tell which one you have? Thank's for any help. john

[Dennis C.]

Re: 58 tach 270 hp vs. 290 hp Question

My 58/60 Manual is up at my shop. My memory says only 290 '58's used the 8K distributor drive tach. But my memory is probably up at the shop too.

[Joe L.]

Re: 58 tach 270 hp vs. 290 hp Question

John-----

The FI distributor driven tach was different than the 270 hp generator driven tach. For 1958-only, the distributor driven tach was GM #1548706. The 1958-only 270 hp generator driven tachometer was GM #1548773. Look for some vestige of one of these 2 numbers on the rear of the tachometer.

By the way, distributor-driven and generator driven tachs for the same, basic application are usually internally different due to the different rotational speeds relative to engine speed of the distributor and generator.

[Dennis C.]

Re: 58 tach 270 hp vs. 290 hp Question

Thanks Joe... I believe on the back of the tach will be a stamping that will indicate what internal gearing the tach is equipped with: eg - calibrated for 1/2 engine speed (dist drive)...

[John S.]

Re: 58 tach 270 hp vs. 290 hp Thanks Guy's

Thanks for the help guy's. Much appreciated, john