Source to locate correct distributor numbers per application?

Thanks very much for all the info guys! I just purchased a 2875989 distributor off Ebay for the owner of the car. Come to discover, whoever did the Pertronix conversion did NOT change the coil. It should have a .6 ohm coil but it has a 2.0 ohm coil. Tech at Pertronix tells me that is a big no no! Rest of the story is, I have to have this car running before the transport gets here to take it to a restoration shop for some very minor body issues. The proper coil should fix the drive-ability issue for the time being, and I can get the distributor rebuilt and ready to go when it gets back.