Installing a Ford type Starter Solenoid
Standard GM Starting Circuit
Starting Circuit w/Ford Solenoid
This kit from Summit Racing (#SUM-G1750) includes all items necessary to install. User might wish to get two new battery cables instead of cutting their existing battery cable. One cable will be needed from the battery (with correct post connection) to one side of the solenoid and a second cable from the solenoid to the GM solenoid on the starter. Note this kit and one from M.A.D. Electrical comes with a metal connector for the GM solenoid to connect the battery post to the inside "S" connection instead of using a jumper wire.
One advantage to using a Ford type solenoid over the 30 Amp relay below is the solenoid posts can be easily reached to crank the engine to do things like a compression test or check to see if the points or plugs are firing and you can bump the engine over to bring the timing mark on the crank into view.
Optional Starting Circuit w/30 Amp Relay
You can also wire a standard Bosch-type 30 Amp relay into the circuit to help with a hot starting problem. A 30 Amp relay is easier to 'hide' than the Ford type solenoid shown above if an original look is important to maintain for your car.