Seems that we are having the same problem due to a lack of information from Langdon's. I did get a drawing of the plumbing for the thermostat housing adapter to roure hot water to the intake.
It appears that the "left side" of the housing is from the drivers seat in the vehicle. This would be the right side from the front of the engine. Water from the right side of the adapter (as viewed from the front of the engine) would be the pass to the intake manifold and then return to the line from the water pump to the heater core. In this example the water would be heated prior to the thermostat opening so it should warm up quicker.
All this said, it took three evening to grind enough clearance for the Offenhauser intake manifold to fit the Fenton headers, again no instructions to go by.
We're fortunate to have this forum to discuss our problems and have others help in the solution.
