RPM AIR-GAP carb spacer?

Thanks for the reply! I was wondering wich HVH spacer you used with your RPM AIR-GAP intake? They offer the ss4150-1a wich is the aluminum 4 hole 1 in. spacer,or the ss 41501p with phenolic plastic 4-hole 1in.they call both of those super suckers,or I see they have the st4150-4 street sweeper wich they recomend for the RPM AIR-GAP .This one is also aluminum? Thanks again!