carburetion · FF-0411

How was the four-barrel ARDUN intake modified for a modern carburetor?

The intake had four holes sized for older, smaller four barrels. The butterflies of a modern 650, or the 750 Steve will run, are too big to clear them. Adapters exist, but he had the holes machined out into one opening, which leaves a hump on each side. The intake was already a single plane; the change removes about an inch of separate runner that might have helped low-end torque, which he says he would have preferred to keep.

Expert

Steve Coppock

Evidence

expert attributed

Component

intake manifold carburetor opening

Applicable scope

Steve Coppock's supercharged ARDUN overhead valve Flathead, mocked up before its dyno test