They've been around quite a while, and are sold under different names by different resellers: Speedmaster, Crosswind, etc. They're all the same. Cast offshore, fits LA and Magnum heads. Ports are a touch small for 340/360 heads, but are a bit larger than 273/318 heads. They seem to match up to the Magnum port "pretty" well. Nothing earth-shattering performance-wise; but they're a decent, inexpensive way to get a 4bbl. on your LA or Magnum.
