Bolt-in for 88-95 inches and stock CR. Good for two-up touring. More torque and horsepower at lower and mid RPM range. Works well with both carb and injection. Stock springs OK. 1800-5200 RPM. These cams are used to convert a 99-06 Twin Cam from the stock ''silent chain drive''; which is equipped with spring adjusters; to the ''roller chain drive'' with hydraulic adjusters that work on engine oil pressure. This roller chain and hydraulic chain adjusting system; which is much better than the early system; is used in all 06-17 Dyna and 07-17 Softail and 07-16 Touring models. Note: Cams are for use with splined (00-up style) driven gear. For 1999 Twin Cams splined 503575 driven gear must be purchased separately. Note: See our catalog for additional required parts.