i built a motor last summer for my offroad truck, i purchased a lunati roller cam for it, when i got the cam summit had mislabled the camshaft on their website, and told me it was my fault so i threw the cam in my motor i got the button and lock plate, i used the factory roller lifters and now i have a lifter ticking, so im wanting to know if it is due to the cam being a retrofit cam, or if i have a plugged up lifter or soemthing, the cam is the same design as a oem roller, only difference is the cam nose is machined for use in an older style block. but any suggestions on what type of lifters i should get? its a standard vortec block with 062 vortech heads and a .500/ .500 lift cam