Is this a number matching thing or just getting a distributor to work? If you have the aluminum Chrysler distributor with points or electronic you just need any Big Block(CCW rotating) vacuum advance with a 9-11 stamp on the distributor. Could be lower too.

If you have the original distributor with retard function that would be different. A picture of the distributor with cap off to see the breaker plate would help get you the correct advice.