I doubt this is individual runner, but it wouldn’t take much to make it that way:
Home made intakeInteresting choice to have the carbs mounted 90 degrees out of phase with the center one. But the way the outer carbs are biased to the center, makes me think it might actually fit in an AD truck.
Perhaps a good starting point for a sufficiently motivated person (not me) to do some three carb experimentation.
(Not my item, just linked for discussion purposes)