Boost leak checker ?
 

While I was putting my IM back on I figured I'd check for a leak. I'm capped off at the cold pipe hose and hear no leaks but quickly fall from 20 psi in less than 5 seconds. Using my cigarette at the tail pipe I'm clearly loosing it through an/the exhaust valve(s).

Normal?

yup normal!
soap down your pipe connections, also it doesn't test your intake, it is building pressure against your TB!

then trickling into the intake were valves are open/ closed so no pressure!

their you will have to do a running test, and use either to spray down the intake connections to check for leaks, as this is the only part in a vacuum!

good luck!

I seem to recall that I could not hold pressure for very long either when I did a boost leak test.

Should have mentioned that I'm holding the TB butterfly open with a wine bottle cork. So I should just open my valve enough to keep it at 10-20 psi and check it with soap water?
Thanks!

Sounds to me like you just got unlucky and one of the cylinders is at BDC between the exhaust/intake strokes. You should be able to bump the engine and get it to a place where the intake and exhaust valves are not open. Leave it in gear to keep it from turning the engine over.

huh i guess you could shove a big potato in the tail pipe, and soap everything lol including the exhaust!