Fast Dual sync distributor question
 

I bought a used dual sync a few years ago and have just installed it. It appears to only have 1 magnet on the distributor shaft , so that only goes by the hall effect sensor 1 time per rotor revolution. Is it missing some parts or is that how its supposed to be? I'm setting it up with a GMPP ram jet 502 harness and ecm (MEFI 4).

My understanding of that operation is that the single magnet is acting as your cam sync. It's telling the ECU when #1 is coming. I don't have literature on that specific distributor, but that magnet is likely 10-30 degrees before the #1 terminal. You would feed that information to your ECU, along with the firing order.

Knowing when #1 is coming and when then allows the ECU to fire spark at specific intervals for each cylinder independently.

Hopefully Scott will chime in on this as I believe he'll have a better explanation.

The instructions had a way to time the distributor at TDC when the crank is 50 deg BTDC.

I'm unfamiliar with those. I'd be looking for something in the area of the reluctor for crankshaft timing. Maybe a second set of wires or such. My understanding was that the dual sync would handle crank and cam signal duties. What brand and model?
ETA: I see now it's that FAST brand.
Contact Lee Atkinson, he has a lot of experience with that brand and is a member here. Send him a PM, he's a good guy and will help if he can.

After taking an admittedly brief look at one in photos, it appears there's a single wire connector which has multiple wires in it. Gives the impression that the cam sync(part that has to be phased) is adjustable and the crank signal is automatically triggered every 45 degrees.(probably off the reluctor) How many wires in the connector? That probably will add some clarity.