I have an obscure mid-1970s machine, the Pacer, made by Product Support Engineering (not AMC). It uses nylon card guides that are 2.5 inches long, have a 0.312 by 0.375 inch cross section, slots down two opposing sides, and a threaded insert in one end for mounting. They are designed to be used on the mounting ears of edge connectors, though the Pacer also uses some attached only to the PCB in cases where the plug-in card is wider than the edge connector. Does anyone know of a source for this style of card guide? My Google searches mostly turn up snap-in card guides, and a few screw-in ones that have screw holes along the long axis.