Turbo Scamp
I've never seen an inter-cooler on the downstream of the radiator. It would be pre-heated by the radiator. I think he's looking at A/C as well so the A/C condensing unit takes away a bit of the charge cooling in itself, at least when the A/C is on. It's best to place the charge cooler as far forward of everything.
GoFish are you planning to use electric cooling fans? That would free up some space between the engine and the rad?
Buddy of mine did a pro-charger on an Eleanor he did for a customer. He used a single elec fan and the car had A/C. Although the Elanore had a bit more room up front than the std Mustang as it has the nose lengthened and I think he located the inter-cooler low on the front away from the rad and A/C condenser. Space is the key - good luck, I'm sure whatever you figure out will work well. Can't wait to see the finished product - great build.