Or you could get a good boost gauge that shows vacuum. There aren't many places for leaks. Pretty easy to check.
Heck, a can of carb cleaner does the trick.
Smoke machines are primarily for evap systems.
I don't disagree with using one. I'm still a little fuzzy on how they work.
blower/vac in up pipe, wire throttle open, spray with soapy water, you will find every vacuum leak, will also work on exhaust leaks, rubber glove and hose over one tailpipe blower in other tailpipe will pressurize exhaust all the way to head, soapy water will find exhaust leaks.