While waiting for OP to answer about the ignition, you might peruse
www.megasquirt.com to learn of crank-triggered ignition options. Most use a 36-1 (or 72-2) toothed wheel on the crankshaft, with a pickup, either 2-wire VR or 3-wire Hall-effect (most Chryslers). The megasquirt processor can accept that square-wave signal directly, using the missing tooth to locate TDC. If you want a dedicated processor, a Ford EDIS 6-cyl box might be used. Its output can drive a coil-pack for "wasted-spark" firing (2 cyl at once). The Ford coil-pack looks a bit goofy IMHO, so I might choose use a Chrysler 3.3/3.8L coilpack. If you want to spark only on the combustion stroke (little advantage), you also need a camshaft sensor. You might adapt one to fit in the distributor hole of a slant, or perhaps modify a slant distributor to work thus. Another little processor would have to "vote" on the EDIS output based on camshaft position, or run it all thru a megasquirt processor. For single-spark, many like the Chevy LS coils which pack a punch and have an integral coil driver so just need a logic-level input signal.
So far, I installed a 36-1 wheel on my 1965 Dart 273, but haven't used it yet. I've pondered that for my 1964 Slant but a bit harder since little room at the front and fewer mounting points for a sensor. In the small-block, I can also leverage the distributor for a Magnum which has a camshaft sensor (for sequential FI, not used for spark).