On my '66 442, the tach is mounted externally on the left side of the dash.
I haven't been able to find out from my manuals whether it is mechanical or electronic. Could someone tell me which it is?
Thanks for your help.

Pat

 

Unless there is a cable going from the distributor to the back of the tach it's electronic.
The only stock car I personally know of that used a cable (jones drive I believe it's called) it the Corvette and I think that even changed in 68, but I could be off on the year.

 

Definitely electronic.

 

As noted, a mechanical tach requires a cable like a speedo cable that is usually driven from the distributor. Olds never used such a system from the factory and frankly you'd be hard pressed to find an aftermarket tach drive distributor for an Olds.

 

@pat: i have the same and posted a similar question, which was answered very fast; plus you can see a picture of that tach from the pcb side:
https://classicoldsmobile.com/forums...highlight=tach

 

Thanks Alex. If I had just read my shop manual more thoroughly, I wouldn't have asked this question. I've located a little shop in Portland which restores instruments and he is going to put a solid state setup in my tach. Mine is working sporadically and the rpm it shows doesn't match with the sound of the engine.

Pat Mills

 

Check it with a test meter to find out just how far off it is.