To me, nothing detracts from a vintage, or vintage style racecar like having a 5" monster tach with a shift light sitting in view. And I don't like to take my eyes off of the track to watch my Sun tach, so I made a shift light for my helmet. Parts needed are: 1. 12v light bulb from Radio Shack. 2. RPM activated switch. I use a Mallory because it has DIP switches and doesn't need pills, but you can use a MSD if you want. 3. 18 ga. wire. 4. Male and female plugs of your choice. (Radio Shack) Mount the RPM activated switch where you have access for changing the activation rpm if necessary - mine is under the dash on the firewall. The wires hook up the same as your tach, or you can splice it into your tach leads. (Follow the instructions that come with it.) Run the light leads to the seat. I installed the light bulb by using a probe to poke small holes in the chin lining of the helmet, and pull the pigtails of the light through. Solder all connections of the wiring and cover with heat shrink.