Can you use a single pole master cylinder switch in an early car that had a two pole?

New master cylinder has a single pole switch and the old (original) master cylinder had a two pole with two wires.

I'm in a time crunch and thought I'd ask the group before digging into the wiring diagrams

Yes you can. I have that now in my '71 with 19mm MC. You have to pick the correct wire to connect to. One of the wires is ground and the other is the bottom (negative) side of the warning light. Leave the ground wire hanging as the switch provides the ground return to light the warning lamp when a fault occurs.

The brown with white stripe is the wire you want to connect. The completely brown wire is the ground.

Coincidentally, I just hooked up by switch last night, so the wiring diagram is fresh in my mind. Although, I'm pretty sure all the completely brown wires in the car are grounds.

Thanks! I was going to ground the brown wire, but if I don't have to, great.

I did a single pole mc on my '71. I just taped off the ground per world recommendation. Worked fine.