I had this problem also. Took out my older Hughes cam to swap in a new Comp cam and it did not fit. Grabbed a used Mopar 484 cam I had on the shelf and it slid in no problem just like the Hughes cam. Started measuring the cam journals and found the older cams were at the low end of the spec. and the new cam was at the high end. Also found the new cam was slightly bent. I took it to the machine shop and had him straighten the cam and polish the journals and after that it fit good. Just cause it is new don't mean it correct, I would be checking your new cam over good before I would start messing with the bearings.