Andrews Y Cam Set for Harley Davidson Ironhead XL 71-84 Biggest available four-cam set that does not require head work; however some 82 engines may require spring spacing Uses stock springs and provides great mid-range and upper end power Use with 9.0:1 to 10.0:1 compression ratios for best power gain Note: 81-E84 cam gear kits (with generators) do not have tachometer drive gears, L84-85 cam gear kits (with alternators) do not have generator Intake Opening (degrees): 35