I have a 74 cuda that I have installed a 68 440 with a A833 trans. I have always loved the ralley dash and decided to put one in the car. I don't have the ralley wiring harness but I did see a add on to change from the standard dash to ralley for 50.00 from roseville. Has anyone bought and used this add on? And what would I really need to do to use the ralley dash? Thanks

Add a tach wire and a power lead to the clock. As I recall the oil wire has a different connector on it as well. I did it like 30 years ago and it's super easy.

Sheldon

Obviously you'd need the Rallye cluster, switch panel, light bar (above the cluster) and the rallye heater control panel, and the rallye radio bezel plate.
I think I may be missing something else?

Ralley's rock! The standard dash oil pressure uses a warning light, the ralley has a gage. You'll have to replace the light socket with a connector that fits the pin used for the oil press gage. You'll need a separate tach wire. It's easier if you rewrap the harness and to get more turn signal wire length. It's all pretty easy.