Description MSD8428 by MSD IGNITION Spark Advance, Street Fire, Mechanical Advance Kit, Weights / Springs, Gm / Street Fire HEI Distributors HEI Advance Curve Kit MSD8428 Kit includes new advance weights, springs and bushings. Fits stock HEI distributors and will deliver solid ignition timing. Will not work with MSD8365 Pro-Billet HEI distributor
