1-piece induction hardened stems Made for unleaded fuels Swirled polished heads Nitrided valves have better heat transfer and promote longer valve train life Sold individually This product can be used with Model Part# Harley-Davidson Panhead 1-7/8 in, 1/8 in oversize H-D#18071-48 48-65 NIVHD-1 Harley-Davidson Shovelhead 1-15/16 in H-D#18075-80 66-84 NIVHD-2 Harley-Davidson Big Twin H-D#18074-83A 84-04 NIVHD-3