This is the "top end" after extensive rework by BJ MacDonald, just prior to reassembly. In addition to the "top end" work, BJ disassembled the engine, trued the crank and welded the crank pin for high rpm reliability, polished the transmission shift drum and forks for smoother performance. The carburetors were disassembled and the bores polished inside. The air box was modified and velocity stacks built for the carburetors.