Continuing with the discussion about factory gauges in race cars:
While I did not race my Camaro on a track, I did (as most Z-owners did) participate in some competition on the street..
Attached below is how I addressed the 'sloppy tach' issue in my 69 Z28 in the 70's when I was driving it regularly. I removed the original tach and the plastic housing around it (and saved it for installation later - which is now..
... then I bought an extra plastic cover and cut out the 'clear face portion', because it interfered with the larger Sun Supertach. I then installed the Sun Supertach in the same location as the factory tach came from the factory, and installed the modified plastic cover. Photo attached. This approach worked for me, because in the late 70's, I didn't want to make any 'non-recoverable' modification to my very original Z28.
Note: I did 'trust' the mechanical oil pressure gauge which came in the console gauge cluster, so I did no other mods to my car (other than a Mallory Rev Pol and Judson electronic magneto, and some internal engine parts.. Forgedtrue pistons, lunati blueprinted cam, etc and it would rev well beyond the 6500 rpm that I *tried* to observe.. most of the time...