Optical ignition?

That is the Accel Copy of the Mallory Unilite that is a replacement for the points in that distributor.

Do yourself a massive favor and get a Mallory 29371 and get it on there.

It goes in line between the wires coming out of the distributor and the harness. It will protect the unilite from dirty power, shitty grounds and other electrical voodoo and hobgoblins.

Never ever jump the engine with the unilite hooked up. Or start the engine with a battery charger hooked up.

The power off that **** will kill the module so fast your head will spin.

Treat it right and the unilite will outlive you.

Don’t press your luck.