How to Install Small Block Chevy Distributors

Hold the distributor in your right hand and the vacuum advance (attached to the rotor) in your right hand with the rotor facing downward to the engine and the cap or cover facing up. Align the distributor over the top of the engine over the distributor mounting holes and the exposed oil pump drive shaft.

Drop the distributor down into the shaft as far as it will go without forcing it. It will typically not go into the shaft all of the way unless you are extremely lucky.

Hold the vacuum advance and turn the rotor counterclockwise until it drops down into the shaft. It will rise up and then fall down into the shaft. This is normal. The oil pump drive key needs to mate with the bottom of the distributor in two directions, each will be 180 degrees apart. There are also 12 gear-tooth positions around the circumference of the distributor drive gear on all small-block Chevy engines. Count them as you turn the rotor.

Do not allow the distributor to fall all of the way down into the next pair of teeth on the distributor drive gear as your turn the rotor counterclockwise. During this process, you will end up skipping ahead 180 degrees and then allowing it to fall into position. Make sure that while you are rotating the distributor, you are still holding the vacuum advance and counting six gear-teeth positions. After counting positions, drop the distributor in place. This should position the rotor in the proper position to be fully seated. Every full revolution of the distributor will seat it an extra 30 degrees clockwise. This, in turn will bring you closer to the No. 1 firing position, which is where you need to be for the distributor to function properly. Keep turning the rotor until the rotor is finally in the 6:30 position (picture a clock as you look down onto the rotor).

Secure the rotor with your engine's supplied mounting bolts.