These dual roller chain sets feature billet gears with hardened teeth. The crank gear has nine key ways for adjusting cam timing in 2, 4, and 6 degree increments (advance or retard). They offer greater strength and reduced chain stretch over stock chains to maintain accurate cam timing, and offer less resistance which aids in decreasing oil temperatures and increasing HP.  They require no modifications to install and will fit under the existing stock timing chain cover without any clearance issues.

Note: In some cases you may need to eliminate the oil slinger (looks like a big washer) for adequate clearance, but this is OK. The oil slinger was used to sling oil away from the crankshaft seal in an effort to reduce oil leaks, however the oil slinger is no longer needed due to improvements in gasket technology.  

NOTE: For 170/200ci engines only. We tried to get one made for a 250ci, but the manufacturer said it couldn't be done. However, we found a way to make one up using parts from two different sets, which requires custom machine work. We're trying to convince the manufacturer to make them for us, but we don't know how far we'll get.