These are the same valves used in our Stage 2 and higher cylinder heads for 3100, 3400, 3500 (LX9) engines.  Valves are stainless steel, undercut on the back side for improved flow, have stelite (harnened) tips for prolonged life.  Sold in sets of 6.

Please note valves larger than stock size will require new valve seats.  Also it is not possible to use both 1.56" exhaust valves and 1.84" intake valves at the same time.  One of them must be smaller to be able to fit.  We recommend 1.84/1.52 for naturally aspirated, and 1.80/1.56 for boosted applications where maximum valve sizes are desired.