You probably don't see it because others have added the tach during their restorations.

It was an option.

I think some original buyers knew they were going put an aftermarket tach in that was more accurate then the factory one for the same or less money. Same for steel wheels. And some Hemi cars that were optional with fresh air hood that didn't really add much performance, but added costs and weight.

And like many Hemi Cuda and AAR don't have tach because they were not optioned with Rallye gauges.

426runnner, I your car a post/sedan or have very few options?