I was able to get out to the hanger today and hunt for vacuum leaks.  There doesn't appear to be very many areas for the the leaks to occur.  I did disassemble the carbs and looked for any tears or holes in the diaphragm.  They looked like they were in good shape.  I also cleaned out a couple of the internal holes that balance the vacuum diaphragm.  I found a little bit of stuff in them, but it didn't change the way the engine ran.  every thing appears to be normal up to about 1/2 throttle which gives me 4800 RPM.  WOT only gets me to 5100 RPM.  The EGT at WOT are 1150 and 1130. 

I have a HACman installed to the carbs, but nothing else is attached to the carbs for vacuum.  I did try disconnecting the HACman and ran a tube to each of the carbs with a hole drilled in the tube for the atmospheric adjustment.  This didn't change the RPM.  The EGT were a little higher.  No other changes that I noticed. 

I did try a mag check at 4000, 4800 and 5100 RPM.  They all check out as normal.  About 150-200 RPM drop at each. 

Anybody have any other suggestions to try for this problem?  I does act like it is something to do with the carbs, but I don't know what else to try.

Thank you
Jim Rieck