I believe mopar specs calls for anywheres from plus 10 to minus 10 on the DRB. Most of them are set near zero. It will run anywhere in that range, just may run like crude until you get it set right. With one of my old cams, i did not have it set right and every morning it would backfire once and then run fine for the rest of the day. After I had it set to near zero it ran great and did not backfire any more.