Old style with slot plate:

If you know what the car needs for initial, which should be first up, and total, then it's easy math and a little work.

http://www.moparmusclemagazine.com/techa...em/viewall.html


Modifying advance slots
degrees / slot size
MUTLIPLY by 2 to get crankshaft degrees
6.............. .340
7................355
8................375
9................390
10...............405
11.5 ...........420
12...............435
13...............445
14...............460
15...............475
16...............490
17...............505
18...............520


Newer mallory style.

Same take apart procedure, use drill bit shanks to hit the mechanical advance instead of the mallory keys. The sizing is posted somewhere on the site.

https://board.moparts.org/ubbthreads/show...amp;Search=true

MRG 925 springs seem to work well for a quicker advance curve.