distributor drive

Hi folks , I am planning a "B" engine build and I have a couple of questions . Is there a roller cam available that doesn't require a bronze distributor drive ? And , if a roller cam requires a cam thrust button , what is the clearance ? Thanks and Merry Christmas and Healthy New Year . Too Tall Tom from Tilton
I run .007 on the cam button clearance on a 505" wedge w/ a solid street roller.