I've got a 66 Coronet with a newer 727 in it. Where or how does the wiring run from the switch in the transmission to the switch at the firewall? Does it run outside the car or does it come in to the interior? Thanks Dennis

It should come up over the top of the trans and join the rest of the wiring on the firewall at the back of the motor.

On my 70 Cuda the BU light wire plugged into the firewall bulkhead connection and the start ground wire plugged into the starter solonoid at the fenderwell.

Thanks