They were in the various Shelby catalogs for several years. By FAR , the best cross ram made for a small block Ford. It could use some "filling" in the base to help direct air flow as a single four. Better than the T/A 289 dula plane ,dual four when the top is switched to run two fours. T/A22 , Gary Goeringer ran one on the Maier Racing '67 coupe he used to own. Well over a thousand were made.
Randy