They have been around for a little while. Chevy used them on a few million of their engines in the '50s and '60s. These were "WCFB"s (white cast four barrel) and "AFB"s (aluminum four barrel), used on both 283-327 small blocks, and the 348-409 engines. Often they were on the high performance versions, like the 409 dual quad engines. Yes they were pretty good.