How to Install a Distributor in a Big Block Mopar

by Floyd Drake III
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Chrysler Corporation, or Mopar, big-block engines are part of the RB engine series, which consists of a few of Mopar's legendary engines - the 383, 413, 426 and 440 cubic-inch. These are big engines, manufactured for performance and heavy applications, including muscle car, marine and truck use. In order to get the best performance from a big-block Mopar engine, the timing needs to be set properly, which is the main goal when installing a distributor. Part of any thorough tune up, timing is initially set at the distributor, then fine tuned when the timing is checked with a timing light.

Step 1

Remove the number one spark plug using a 5/8-inch spark plug socket and a socket wrench. The engine needs to be manually cranked until the number one cylinder piston is at top-dead center, or TDC. To crank the engine, place a long socket wrench with an extension and socket on the main fan belt pulley bolt and turn the wrench so the engine turns. The main belt pulley is located at the front of the engine, in line with the crankshaft, and may be a tight squeeze. Crank the engine manually until number one piston is at its farthest upward stroke; the top of the piston can be felt by inserting your finger, or a small wooden dowel, into the spark plug hole - this is TDC.

Step 2

Bring the damper timing mark to the center timing arrow by cranking the engine in either direction - the two should already be close when the piston is at TDC. The vibration damper is a metal wheel with a timing mark on the outside rim, immediately behind the main belt pulley. It may be necessary to clean the edge of the vibration damper and the timing arrow attached to the engine block directly above it. Mark the timing mark and the center arrow with white chalk.

Step 3

Follow the number one spark plug wire to the distributor, which is at the front on Chrysler big-block engines. Mark the distributor cap with chalk to identify the number one spark plug wire location. Remove the distributor cap. When the engine is at TDC, the rotor at the distributor's center should be pointing towards the number one spark plug wire, if not, turn the distributor until it is. Remove the distributor hold-down bolt to move the distributor.

Step 4

Slide the old distributor out of the engine. When removing, take the old distributor cap off, but leave it connected to the spark plug wires. Note the location of the metal vacuum housing on the side of the distributor.

Step 5

Insert the new distributor into the engine, being sure to replace it so the vacuum housing is in the same position as the old distributor. In order for the distributor shaft to go into the engine completely, it needs to mesh with the oil pump gear. This may require manually cranking the engine slightly to jiggle the distributor shaft in.

Step 6

Install the new rotor to the distributor and check to see if it lines up with the number one spark plug wire on the old distributor cap. Minor adjustments can be made by rotating the distributor in either direction. Re-attach the distributor cap when finished.

Step 7

Adjust the timing with a timing light according to Chrysler procedure. Keep the distributor hold-down bolt loose during the timing adjustment process, tightening it when the procedure is completed.

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