yes i have run 50" over atmospheric boost before and will be running more soon once my new pump is in. however for now im running 50" absolute cruising at 85 the waste gate is set at 75" HG absolute right now. my boost pressure gauge is actually a dual manifold pressure gauge from an aircraft with the first indicating manifold pressure and the second exhaust drive pressure (around 62-68" @ 50" MAP). mind you im running a holset HE221W with a 7.5 cm housing the stock waste gate spring on it was originally 28 psi turned that down after having some fun for a bit with the sounds it made.

__________________
1985 300D om617: 8mm M pump 175cc 5200rpm, holset he221w @ 30psi, large A2W ic, compounds on the way.
KD9AFT
A&P