[Ronnieroadster]

Joe while i have no experience with the camden blower I remember years back when they were first offered I spent time looking them over. Since your getting 4 lbs of boost at 4 grand at this point thats not to bad. To gain more boost the drive ratio needs to be adjusted so going down 1/4 inch in diameter on the blower would give you another 2 to 3 pounds. If going smaller on the upper pulley is not possible doing the same by increasing the lower pulley diameter would also give you more boost.
Something to remember about the Flathead port design seeing high boost readings is not truly an indication of the pressure the cylinder is seeing. The poor port design is actually a choke to the boost so the high readings are caused by a backup of flow.
Back when i ran my 671 GMC combination I would always see over 20 pounds of boost with no ill effects to the engine even in street driven form as long as a good octane gas was being used when the boost was getting high. That old reliable 671 combination is waiting for a new owner complete bolt on for the Flathead as some say go big or go home. LOL
Ronnieroadster