Years ago I would do my own distributors and I bought the kit that had light, medium and heavy springs. I always used a light and a heavy spring but with the stock weights this is with a points Dizzy. I also used go to junkyards then I would look for old distributors and look on the bottom of the 8 lobe cam part to see the numbers, like, CCW 20 or CCW 30 or something like that, make sure you never use one from a Buick Olds or Pontiac as the their Dizzy's rotate the other way CW (found that out the hard way). The numbers were the amount of advance with the slot, then you add in your initial timing and get your total of 38° or what ever you want. I hated doing HEI Dizzy's as they suck, hardly ever used them except in my race car that has a locked in Dizzy so I do not have to fool around with it. I like the MSD Dizzy's as they have a little bushing you can put in to get the amount of advance you want.
