Carter AFB competition 625CFM
I'd start at a turn and a half but it really doesn't matter.
Timing is 6 btdc and 35 with vacuum connected.
In almost all case, initial timing is set with the vaccum advance disconnected and the vacuum source plugged. Golf tee in the hose is convenient.
The rpm at which timing is set is also important. It could be as low as 550 or as high as 900 on (a few) smogged engines around 1971.
Do that first.
Then tweak the idle mixes for strongest vacuum in highest rpm.
Then working toward lean go 1/8 turn at a time.
As soon as rpm or vac drops, turn the screw 1/4 turn richer.
That should be close to the strongest mixture in gear. In gear is what is important.
With an automatic you can out your foot on the brake and shift into gear ands see the rpm and vacuum drop. The least drop is the strongest mixture and timing,
