These sprockets are made from heat treated alloy steel with a wider than stock press fit for greater stability. The early style cam sprocket features a stronger than stock full length 3/16" drive key that won't break and includes 3 shims. With the shims, the installed length of new sprockets can be set to the same length of an original stock sprocket plus spacer. Because of the stronger and much more rigid mount than the OEM sprocket, it is highly recommended for use in your engine even when using the stock cam but must be used when installing a high performance Andrews cam. Optionally this rear cam sprocket may be combined with Andrews heat treated steel 17 tooth crank sprocket. There is also a top quality splined cam sprocket available for 2000 and later models but this can also be used when you want to use late style splined cams in your early 1999 model. Can also be used in combination with ZPN700737 crank sprocket. We suggest you to replace the stock cam sprocket ball bearing with Heavy Duty roller bearing.