Can't advance timing?

Cope said
...I can't get anymore than 50 BTDC. ....

You need to step back and re-think "whut?"

Cope said
50 deg BTDC at idle is what I have. I want to bring it up to 5-10 BTDC

5-10 is not advancing from 50, it's retarding. You move the dist CLOCKWISE on a SB to retard it.

50 would normally be way too much timing, whether total or idle. 35 or maybe 40 max

Move the plug wires one hole

Pull the distributor, walk the gear up out of the helix and move it.

Make sure you are reading what you think you are, and that you DO NOT have a "dial up" timing light that is screwing you all up