I run a small (2 and 1/4 inch) tach that I attached to my steering column. Wouldn’t do without it. There was a console tach (same size and fits exactly in the console like the turbo gauge) that was put in upper level Oldsmobiles in 62-63 (I’m fairly certain they went in Starfires in the floor shift console. ) If you don’t like your turbo gauge, you could swap it out for one of these tachs with no modifications whatsoever. I went the other way – I found a 4 speed console with a tach and swapped in the turbo gauge. Still have the tach if anyone is interested in it, though it would likely need to be rebuilt. It is beautiful, however, same look as the turbo gauge.