440 roller cam conversion parts list.

For my own edumication, is the distributor shaft required because it's a roller or are you just getting a new one "because"?
To be honest it’s just what i understood was needed. Something about flat tappet cam and lifter design are what help keep the cam centered. I haven’t had any real experience so that’s one reason I started this thread. To gain knowledge as to what is needed to make the switch.