Howdy Back Jay:
Check out the Summit (page 83) performance or Jeg's catalog. Most Parts stores have a wall section for performance/dress up- check there. They usually come in a kit that includes a new, adjustible vacuum cannister. The cannister may not fit your distributor.
They won't be listed for a six, but the V8s are the same springs. Also no difference in points or electronic springs- just tension. HEI and Delco springs have a little different shape, but also work.
Tension varies due to diameter of wire and number of coils. Smaller diameter is softer, more coils is softer.
While you're down there clean and lube to posts with silicone or a small amount of dialectic grease.
Adios, David
