[steve25]

Since your breaking in a new Cam it would seem would go with 18 to 20 degrees.

This will make the motor less likely to stall and run hot during the 20 minute Cam break in period as your getting other things sorted out.
Be sure to prime the Carb with fuel tru the air horn vent until the accelerator pump is seen to work well.

If this is the original Carb that was previously running on the old motor then turn up the idle speed screw by one full turn .so that you have 2200 to 2400 rpm taking place .

Note that the the motor is at #1 TDC when you see #6 Exh valve opening.

Also if you have the good full size balancer and you measure around from the timing notch another 2 1/8” that should check out at 38 degrees or so with the vacuum advance disconnected and plugged.