Different size bearing bores isn't just a Chrysler thing. BBC mark 4's are different too. Dart big m's come with a tech sheet that shows cam bearings to be standard BBC however they have all the bearing bores at 2.120, and there is a special number for those. My little rant. Most cam bearing tools you drive in with a hammer. Sometimes you will leave them a little funny hence the reaming/scraping begins. I have an older OTC tool that draws the bearings in with a bearing and a threaded nut. Once I learned the proper amount of Jiggle between the collet and bearing shell before installation things go much better now.