what is the best way to see if you have one? i'm suspecting i might be loosing some vacuum internally. thanx mike

Internally... Where? I've got a leak in the passenger compartment of the nomad. Do you mean like in the carb or elsewhere in the engine?

To check for an internal vacuum leak to the crankcase...

Remove any breathers and the PCV valve from the rocker covers, plug the holes with your thumbs.

If you feel vacuum there, you have an internal leak to the crankcase. You should actually feel a slight amount of pressure trying to escape from under your thumbs.