I should have asked your advice before I started this Roller deal Chryco!!
:grinyes:Here's what I had to do. The rear welch plug is obviously installed. To check the proper thrust clearance I had to grind then radius the cam button a bit, repeated trips to the sioux grinding machine to remove .010 at a time then mock it up and check it. After 7 times I had the required clearance which is easier to hear it tap the inside of the cover than to feel for .010 with a large screwdriver against the cam lobe taking care not to scratch a lobe. Clay helps to get a baseline, if the cover wont go on at all then the button will have to be either changed to a different style or it will have to be severly ground, some buttons wont allow this like the Diamond,, a Crane/Comp alluminum will work ,,I havent tried the Nylon which might actually be a better choice depending on the type of cover you decide to use.