http://rmcavoy.freeshell.org/HEI.html Finding an HEI Distributor There are a couple of choices here, new or used. If you go the used route as I did, it's a good idea to re-build it. In addition, here are a few things to note: '75 to '79 ('75 to '85 Canadian) used 4-pin modules. Some later models used a 5-pin module (for a knock sensor) Computer controlled engines used a 7-pin module When replacing a points distributor, you should use a distributor with the 4-pin module. You could also use a distributor with a 5-pin module and replace the module with a 4-pin one. That would require plugging the extra hole in the housing where the connector for the knock sensor wiring used to be. Distributors using 7-pin modules can not be converted to non-computer controlled use since they do not have advance mechanisms (they use the computer to control the advance). Also note that different GM divisions used distributors with different shafts and gears. So make sure that your used distributor came from the same type of engine that you plan to install it in. Laita tilalle perus 4 -pinninen, niin silloin se olisi ihan perus-HEI.