'69 Corvette vacuum leak?

[Dave Rifkin]

Last year I purchased a 1969 Corvette L46 coupe. One of the first things I did was to take it to Contes Corvettes in Vineland, NJ to have them go over the car and give it a tune-up.
When I got it back the guys told me that it was a very nice, unmolested car but, they could not get the idle down where it should be due to a suspected vacuum leak somewhere.
I have been told that I should take it somewhere that has a "smoke machine" so they can locate the leak and make the necessary repairs.

Is a smoke machine something that I can simulate at home; I don't know of any shops locally that would have such a machine that I can trust.

Thanks, Dave