What color is this car on the trim tag?
Dana had a house drag car 68 Camaro that was a special order Orange and another found documented Dana 68 Camaro is Orange also.
Doesn't mean a a lot but curious what color your car is.
Also Dana used their emblem on some of the 427 cars so if you have original fenders you can look for extra holes. An NICB report is hard to get but can tell you the original dealer.
I collect old speed parts and have some 60's - 70s rev limiters. The ones I have are cable driven off a tach drive dist. They have a centrifical governer divice inside a box with an adjustable switch. The weights on the governer trip the switch at a set RPM and shuts off power to the coil.
cool old speed part
pic is the 68 Dana drag car