Im going to be replacing mine soon , should i go all oem replacement from cloyes or go with their double roller chain set ?? if i get the cloyes double roller set with the 3 keyways , which key way would be best to use , 4deg adv or 4deg retard or straight up and why ? I have over 94,000 miles on my truck and the motor has never been gone through as far as i know/can see . I dont notice any unusal noises coming from the front of the motor but my timeing mark constantly jumps all over the place at idle from 17deg down to 7-8 deg and back up to 18-20 deg and more ( dial back timeing light on # 1 wire and useing the tdc mark on cover as reference point ), and you can also see it changing up and down on the scan tool also . im hopeing a new timeing set will help my engine from acting so sluggish with hardly no bottom end , no power going up hills unless you keep it floord , trans struggling by shifting down and up to keep speed . I have new cat and exhaust system , fresh full tune up with quality oem parts , all new sensors on engine ( except the crank sensor ), belly pan gasket replaced , trans filter and fluids changed , and it`s not overheating . Really isnt anything more to change externally on engine to solve problem ! Thanks for your input !