Reading your post, and then reading my carburetor resources has me confused.
My sources suggest that a 1944 truck would be military only.
If this is true, the military carburetors were designed for high torque LOW RPM. I have no idea what might have been done internally to the engine.
If you have the military engine and carburetor, maybe 5 HP could be acquired by replacing the military Carter W-1 with a civilian Carter W-1.
BEFORE DOING ANYTHING: I would suggest determining exactly what you have.
Jon.
