Is this a bad idea?

Thank you all for your input! Sound like there are a lot of mixed reviews on this subject. My dart runs at 2350 rpm at 55 and 2780 at 65 verses a little over 2000 rpm at 65 with the OD tranny (calculated). I have 25.2" tires and 3.21 rear on the beast. I'm not sure what the power range is for the 318 4 barrel. Maybe 2000 rpm will lug the engine on a hill at 65 mph.