"NOT" Like a glove

just re-looked at your pics. see you still have the heater motor, must be over farther in the dart, or your using a 400 block-?----curious,my pass. side head covesr 1/3 of the heater motor hole-------bob
or your engine is setting lower than mine. the trans bolts were a ***** on mine too----bob

AC blower motor is smaller diameter. Due to the non-stock heads and six pack, use a modern compressor and pulleys to match. Custom hoses to match the factory air box and condensor. We reinstalled the stock AC with the big block pulley in my old 67 Barracuda that we put a 383 in, but the 383 came from an AC car and I just mixed and matched all the parts to make it fit.

Radiators are all in what you want. Aluminum is the easiest, all the way from the low-cost Summit house brand to expensive custom fit units. It's all in what you want to spend.