No spark

If you want to keep the ammeter, you must make certain it itself is in good condition. "I simply would not." And I like ammeters

The MAD thing creates a somewhat tricky parallel path, which causes both the original black alternator wire and the original red ammeter wire to become in parallel as one bigger wire to supply electrical loads from within the car. This part is goo. But to do so either the bulkhead terminals must be in good shape or run wire clear through

Crackedback advocates making sure this is so and then simply connecting a big jumper from battery to alternator WITH FUSE/ breaker in that wire. This is simple and works

There are a few ways to do this.

If you study the factory diagrams around 68is to 72ish and look for the modification for 65A optional alternators, there was a factory setup called "fleet/ taxi/ police" wiring, that was in fact a partial bypass OF THE BULKHEAD. It involved a larger gauge wire fed through a separate grommet--separate from the bulkead.