Blox Racing MLS Head Gasket 81mm Bore 0.030in Thick - Honda LS/VTEC B18A/B B20B with VTEC HEAD - BXFL-00500-81Blox Racing MLS Head Gasket 81mm Bore 0. 030in Thick Honda LS VTEC B18A B B20B with VTEC HEAD BLOX Racing is excited to introduce its new line of metal head gaskets. These 3 layer MLS head gaskets are being introduced for Honda B series engines in 81mm and 84mm bore sizes, respectively. BLOX Racing MLS metal head gaskets are specially designed to be used in conjunction with BLOX Racing's LS VTEC conversion kits, for B16 B18 or B20 blocks, but are also