Here's the rub; I'm dissatified with the default Revmaster Revflow carb mount.   There is no fixed mounting to attach the carb to the engine.  The carb is connected by a section of 38mm rubber tubing clamped to the carb body and the intake induction manifold.

The Revmaster-defined installation specifies a ram tube to send unfiltered air into the carb.  Effective, yes, benefitting long engine life, probably not...

The concept is to use warmed air in the lower cowl pleneum as the source for carb heat.   By closing the valve in the ram tube, warm air is drawn through the filter hopefully enough to take care of any ice (carb or induction) that may have formed.

The builder fabricated this heat "box" to surround the filter.  Note: The poor fit is due to just placing everything together for this picture...

It draws ambient air from this heat shroud which is installed around the 4-into-1 collector.

I found these shots from a link off Mark Langford's site. Here's a nice looking installation, but I'd prefer to have an air filter for all the air entering the carb...