Vintage Stewart Warner tach with pertronix

Gentlemen,
I am trying to get a working tach setup in my '67 satellite and am having issues.

I have a Stewart Warner greenline 6k electronic tach 432967, but can't find a sending unit for v8.

1) Does anyone know if there is an aftermarket/reproduction v8 sending unit that will work on this tach, or do I have to get the vintage auto meter part?
2) If you have a good v8 sending unit or know of where I can buy one, it would be greatly appreciated.
3) I have a gen 1 pertronix ignition (basically just swaps points for a magnetic pickup), negative wire coming off coil to tach sending unit should still work right? I don't think the gen 1 pertronix is a true electronic ignition, it has no ecu.