You can keep the 351C distributor if you want to. But you can also put in a High Energy Ignition (HEI). The distributor from a 460 (big block) drops right in. Find your basic Lincoln Continental in the junk yard. Look for the distributor that has the Dura-Spark II. The others are not as good (I don't know exactly why). Get one with a vacuum advance. These are in the 1975 to 1979 engines. I got mine from a 1976 Lincoln Towncar.
Years ago, there was a "Ford V8 Workshop" website. Bill had a lot of information there about this interchange. He took down the site. Some of these are Bill's pictures, others I got out of a Chilton's Manual. Bill, if you don't want me to use your pics, email me. I will get my own, otherwise, thanks Bill!
Basically, you need to get the distributor, the distributor cap, the coil, stator and the module itself. Here are some pics.