Premium stainless steel, swirl polished, under-cut stem. EXHAUST VALVES - SINGLE GROOVE (SOLD INDIVIDUALLY) PART NUMBER APPLICATION HEADDIAMETER TIPLENGTH TOTALLENGTH STEMDIAMETER GROOVETYPE VALVEWEIGHT DESCRIPTION M-6505-G302* GT-40 Iron HeadM-6049-L302/303Ford Racing Aluminum Head M-6049-X306/X307 1.540" 0.383" 5.078" 11/32" Square Cut 120 Premium stainless steel, swirl polished, under-cut stem. M-6505-B304* M-6049-Z304D/Z304DA 1.600" 0.290" 5.365" 11/32" Square Cut 120 Premium stainless steel and swirl polished. M-6505-D3047* M-6049-Z304DA7 1.600" 0.340" 5.365" 7 MM Bead lock 95.4 grams Premium stainless steel and swirl polished. M-6505-A351* M-6049-N351/R351 1.600" 0.250" 5.140" 11/32" Square Cut NA Premium stainless steel. M-6505-A429* CJ/SCJ AluminumM-6049-A429/B429/C429,M-6049-SCJ/SCJA/SCJB