A friend of mine just picked up a "Kleindienst engineering" 4 barrell, takes a Rottenchester carbie. It has much longer runners than the clifford. Sorry no pics - scanner is KaPut.
No on Offenhauser. Clifford is the only one that makes one today; I've got one from fifty years ago with no names or numbers on it that showed up in an old Wayne catalog.
i have one, i believe it is an offy. if you want it pm me. i would like to sell it. it has provision for water heat.
Those all take carbs with more or less the same size primary and secondary sides? Have to wonder if you had a Rochester with the big secondaries on there if you wouldn't want it oriented sideways instead of front-to-back.
Viper was selling one in the 70's, but I believe the company no longer exists. They used to specialize in 6 banger stuff. Bob