BBK 1583 Twin 52mm Throttle Body Gasket Kit for GM Twin 305/350 BBK is your Number One Aftermarket Performance Brand in the USA - American Designed and Built Premium Gasket Material Ensures Leak Free Seal Every Time Complete Set of Gaskets Required to Install Stock or Aftermarket Throttle Body, Port Matched For Optimum Air Flow Designed for Higher Temperature Performance Applications Sold as Complete Kits Only