I recently built a 383 for my Duster i used a 509 lift mopar performance cam with stock rocker arms, it runs rough and when i bring up the RPM's it cracks and bangs out the exhaust. I have been told i need to use adjustable rocker arms with this big of a cam and the issues i'm having is caused by the valves not opening and shutting correctly. Do i need to go with roller rockers or am i overlooking something? I have a set of 1.5 rockers but i have no idea how to set them up because i never used them before. A little more info. it's bored .040 over and i'm running a 750cfm carb.