Well this technically would go into either electronics or body or interior, but I think I'll put it here since it's gauge related. I've been thinking of doing this for years.

I just ordered all the necessary parts to build an F1-style tach indicator. It's basically LED's that light up with the tach, more light up the higher you rev. Can be built with any color combo. It's been done before, but usually steering column mounted or HUD style to reflect in the windshield.

I'm thinking I will mount mine in the scoop on my formula's hood. Kind of like an 80-81 turbo t/a's boost gauge that lights progressively.

Any thoughts, opinions or recommendations? I had a hard time picking a color scheme, but I think I'm going with a pontiac orange-like shade. I've got enough LED's coming to change it to green, yellow and red as well.

More good news, everything was so expensive individually to make it, I bought in bulk, enough to build like 5 of them. So there's no excuses to not get one working one built. Should be enough to do my buddy's car and hopefully 3 more.