Magnum distributor on carb'd motor?

Depends on the year.

If the distributor has the half circle interrupter with Hall sensor it will not, unless you only want to fire on one cylinder. If you make your own interrupter it might work. You might need a pull up resistor on the Hall output and invert the signal.

I think they were crank triggered by a tone wheel at the converter, the distributor phased spark and served as timing 720 deg reference for EFI.

I made my own, starting with a NOS lean burn distributor, added an Opto switch and a Mallory interrupter from the SB Uni-lite. That was easier than making the interrupter pan with 8 accurate slots. You could use a Unitlte conversion with a 100 Ohm pull-up, replacing the coil. I used my own Opto to save cost, but needed to fabricate mount.

The Mallory rotor/shutter wheel part number is #334. The interrupter wheel is about 2" in diameter compared to the ~ 1" OEM reluctor diameter you can get more precise timing, and if you file the wheel edges, using a decent degree wheel at the crank, to even get better. An Optical is zero speed, so you can static time and find the exact switching angle. I use a scope to look at the analog value, in switch transition.

Adding 3 #6 set screws to rotor cam locks it to the distributor shaft. If there is vacuum advance plate, lock it with a screw. I use 3 screws and carefully tighten, if one screw is used, there can be a run-out of about 0.002". There is about 40 degrees of timing capability with standard rotor tip and cap terminals. Add that to 15 degrees base timing, there is plenty of advance capability. It is necessary to set the base phase at the trailing rotor tip to cap terminal.

If you want to make more substantial gains consider crank fire, it gets around the drive gear and timing chain errors.