Wild RT you are outta control!!!
YOU should be a Mod!
I never had much luck with the clutch fans, run an 18" stainless flexfan, at least 1/3 into the shroud.
Rule of thumb, after about 35MPH the fan don't do nothing.Air flow from grille takes over.
A smart fellow once told me to think of air as a fluid, one needs to direct it and dam it to where it's wanted.See if there's anywhere you can put in some easy sheetmetal or plastic 'dams' in front of the core to channel and/or block off any air from spilling around the front outside of the core, and force it to got THROUGH the core.
MrG makes a large window 180'harris type thermostat for about 10.00 too.