Help dismantling ThermoQuad

Soaked further with WD-40 and it finally let go.

Working on the 6518S "440 Industrial" carb first. Looks to have the same rods and main jets as is listed for the 6319S '73 340 carb, so I shouldn't be too far off. Not sure about secondaries yet.

I already has brass floats, so I assume that means it was rebuilt before?

Does anyone know what the "Industrial 440's" were used for? (Irrigation pumps and grain harvesters come to mind, being an old farm kid.)