I'm not sure which carb shoot out you are referencing. The carb shoot out article from above is dated 2012 and manifold shoot out 2008.
Here is my cautionary note to the lovers of the RPM intake. No manifold does everything the best. And 383s are not 440s. IMO a 1 hp/cuin street driven 440, will probably be best suited with the RPM, a 1 hp/cuin 383 will probably be better suited with a Performer, or other dual plane intake IMO.
In Shoot Out 1, the 383 was making over 450 hp, and the RPM intake slightly out performed the other aluminum dual plane intakes in the upper rpm range, and about even or slightly under performing in the lower rpm range. Personally, in shoot out 1, I would pick the RPM if that was my 450 hp 383. But in reality there are very very few stock stroke 383 making anywhere near that power. That motor in SO1 had 10.3:1 CR, light weight diamond racing pistons, a medium size cam with the most aggressive racing solid flat tappet lobes made by Comp Cams. It is highly unlikely an inherited "mild" 383 will even be close to 400 hp. That, coupled with the fact the short stroke 383 struggles with low end torque, I would generally give the nod to one of the other dual plane intakes.