If you've kept the factory AC plastic vacuum reservoir tank and the FICD & A/C magnetic vacuum valves it should be easy. The Vacuum tank has a one way check valve in the line just before the Tank ( underneath the relay cover ). Just connect the AC vacuum feed line to one of the legs on the Cannon manifold. That will cover your vacuum operated Heater/AC dash pots. If the manifold does not have a vacuum port, drill and tap one for a 1/8th pipe thread. The heavy pulsation of connecting a vacuum source to one leg on an ITB manifold does not matter in this case because the Vacuum tank will act as an accumulator and the 1 way check valve will prevent vacuum from draining from the tank. ITB manifolds will actually pull a very strong vacuum signal...but with pulses. This tends to screw up a distributor vacuum advance which is connected directly to a manifold leg, but should not affect the Factory AC vacuum reservoir system because of the Reservoir tank. To run a Vacuum advance properly with Triples, you have to build a manifold log to dampen the fluctuations. . If you find that you need an AC throttle kicker, it might be best to toss the factory Vacuum dash-pot kicker and utilize an electric solenoid that extends when 12 volts is applied. You can easily splice that into the AC clutch 12 v line and fabricate a bracket for the Triples. Modify the main linkage rod with a Tab, so that solenoid " kicks " the main throttle rod when the AC comes on.