[Big-Foot]

It sounds like you have the idle set just a little too high. When you have a cam with a longer than stock duration, you typically need more air at an idle, but can't get more air without giving it more fuel to boot. I would advise adjusting the throttle stop for the secondaries to open them just the slightest of cracks so you can turn the idle speed screw in the primaries down far enough where the main metering system can go back to rest at an idle. If the screw is turned in too far, you have uncovered the fuel transfer slot for the primaries and it is now running very rich for a low RPM. That will the cause run-on (used to be known as Dieseling) condition you are experiencing.