I used the spring kit(two littlke thin springs) Mr Gaskets sells for Chevorlets in a newer MSD Mopar distributor two weeks ago, the customer didn't have the kit with the bushings and springs that come with the distributors when you buy them new. Thoe new springs retarded the timing when shut off so the car would start fine and they advanced so it had 34 degrees at 1200 RPM and higher