How much space is there between the grille and deflector panels, or anything else.......

I need to mount a heat exchanger in between the core support rails. not having a grille yet makes it difficult to get an idea of how thick of heat excahnger I can get!

 

From backside of grill at top to the deflector panel louver =1 3/4"
Backside of grill to deflector panel inboard of louvers at top=2 1/4"

Looks to me like the limiting factor is the radiator support cross bracing which is at 3 3/4" from backside of the grill. I doubt if your CAC will extend into the deflector area.
Measurements taken from a stock 1956 F350 272 Y block.
HTH