go for a junkyard crawl..
in the 68-72 chevy truck world..
a lot of people use the 79-81 camaro tach in the spot for the clock.. and it looks factory..
look around.. many factory cars have a tach..
changing the needle color to match isn't hard..
nor is having a vinyl gauge face made to match the look of your build.. to put over the junkyard find..
if you look at my journal, you'll see what I did for spacer rings,, I use wood..