Are you referring to the RPM drop test to pick out which cylinder is misfiring?
Absolutely it can be used on a distributer engine! Disconnect a spark plug wire one at a time with the engine running and see which one doesn't effect the engine operation.
Any cylinder you disconnect that doesn't result in a drop in RPM is not contributing.
Obviously however if you disconnect the ignition coil plug wire feeding the distributer cap, the engine will stall.
Sometimes I find it hard to tell on V8 engines if there is a change in RPM, so I'll leave a cylinder disconnected (with a ground path for the spark, like a spark tester or something so as not to hurt the ignition coil) while I check the rest of them.
