Timing gears

Hi guys
Been awhile since I've been on this site, and a while back
while on the way home, my 74 Dart died on the street, luckly I got to the side
of the road and had AAA pick me and the car up...Damn I was only half mile from
my house. Ok, so I thought it was the ignition module but when I replaced it, nothing
so I took the Dist cap of and tried kicking her over... fine except the rotor did not move.
Right away I got on the net and bought a new gear set S.A. Gear
It's one of these that three key ways,
Questions becomes what timing should I set it at.
0= Factory setting
A= Camshaft advance 4 deg

Any input will be appreciated