Post some pics of the intake in full and show the flanges if you can, be some good oddball tech stuff to archive away. As far as the filters go, every vintage photo I've seen (and there aren't many) show the red filter stampings on both Max Wedge and Race Hemi's, 66-67 Street Hemi's had the blue filters (for certain). The same vendor who made yours (Quiery Engineering) also makes them with the red stamps.