If the "WTeng" sensor location is somewhere in the engine block and not at the coolant outlet and the "WTout" sensor is in the coolant exiting the engine, then the coolant flow rate through the system may need to be increased by enlarging the radiator connections.  Typically, it seems that at normal operating temps, the delta-T across the engine and across the radiators is about 15 deg F.

It also would appear that the mass air flow through the radiators may need to be increased since the air delta T is quite large and the temp of the air exiting the radiators is close to temp of the coolant exiting the radiators.  If your OAT were increased to 100 deg F, you could see "WTout" of ~250 deg F with the setup as it is now.

The attached plots show the effect of changing only the air inlet and outlet areas of my system which has ~0.9" id plumbing to the single radiator.  

FWIW

Steve Boese