Rochester B, BC, BV, H 1 barrel carburetor main jet. Also fits 2G, 2GC, 2GV, 2 barrel carburetors. Jet sizes are usually stamped on the top of the jet, or use a drill bit to determine your existing size.
Includes 1 jet.Rochester B, BC, BV Jet Size SpecificationsRochester 2G, 2GC, 2GV Jet Size Specifications
To determine if you have the correct jets in your carburetor, operate your vehicle for 20 minutes at sustained speeds. Stop and pull a plug. Gray - Good, Black - move down one jet size, White - move up one jet size. Do it all over again until you get a gray plug.
This assumes your engine and electrical system is in good running order.