slayte

I'd like to swap out the guts of my mechanical tach with an electrical one for the time being (keeping the original face & enclosure). Is anyone aware of a suitable electronic donor tach that has roughly the same scale as my original face, or one that can be calibrated to match the original scale?

Or is there a better way to do this? I know there are places that will do the swap for me but I'm trying to keep the cost down.

This is a '65 with a 6500 redline (though I don't think the redline matters since they all used the same 7000 rpm scale).

Thanks!

cbernhardt

I can't help with a specific electronic tach that would work in a midyear, but when I did the tach in my '62 I measured the amount of needle "swing" for 6000 rpm on the original and then looked on ebay for a tach with the same swing. I found an appropriate Autometer model for about $25. One of the things that you may look out for (if it makes a difference to you) is the fact that some tachs do not point to "0" until they are powered up. In other words, with the key off, the tach might register 1000 rpm.

Charles

blandacre

I replaced the "guts" of the tach on my 62 with a kind of generic tach from NAPA. Slight modification of the original tach housing to mount the electric tach. I used my original tach face and needle. Looks original, works great.
Bud

66since71

Problem is that the Corvette tachs go from 0 to 7000, while most aftermarket ones go 0 to 8000. Turns out around 1975 that Corvettes went electronic. I have heard that swapping the internals is not too hard, but I have no direct experience.

gldnkngt

most of the aftermarkets that go to 8000 have an adjustable (variable resister) that you can play with just a bit if you have access to the bench equipment to monitor it. It's hard to get them exact, but you can come pretty close.

Russ T Gate

I just did mine in my 67. I used a Auto meter 270* sweep with 8,000 rpm's. The face was 3 3/8". I had to make up several brackets to adapt it to the orignal mount without any modifications to the stock housing. It works fine but the rpms are off a little because of the 8,000 rpm tach on a 7,000 face, but I can live with it for now. I found a 3 3/8 270* sweep with 7,000 rpm thru Summit for $69.95. This tach is made by VDO and carries PN. 333355. I'm sure this will work and will purchase one in the near future.
Good luck
Russ

mredi1

I sent my 65 cluster to John at Red Line - http://www.redlineg.com/ . He converted the tach to electric for my LS2 engine and converted the ampmeter to a volt meter for me. Came back line new, great work and good prices.

gldnkngt

John does nice work

wombvette

I used a 75 unit in my 66. Used the 66 face, but had to use the 75 needle cut down a bit. No one would notice unless you point it out.

slayte

Thanks for the many suggestions. I'm going to try to find a used 75-77 unit as a donor. If anyone has a lead on a one please let me know.

66since71

Don't forget to post on the C-3 forums for it..

slayte

Doh! Thanks...without thinking I had already posted this on the C1/C2 forum.:o

66since71

Sorry, just that sometimes I forget the obvious... so wrapped up in details.. I thought it might be a more common affliction (comes on with age too..)