Vintage Air for a '53 panel truck..help?!

[joplinrod]

We're building a '53 Ford panel truck with mustangII front, 302 aod the works. Our Vintage Air dealers have suggested the GenIV Magnum. So we got the mockup unit and it really isn't fitting well in there. We'll have issues with the glovebox door, ashtray, radio (placed low in center of dash) and the defrost vent ports. We'd like to use the GenII Super because of the defrost/vent ports face up and the overall shape and size of the unit. I read that KUL FIR CHICK N said that the GenIV and GenII Super, both had the same SCFM rate. If we heavily isulated and weatherstripped the truck, could we use the GenII Super? We've used the GenII compact and mini before in previous builds and they performed extreamly well, and we are hoping to use the Super for size, duct connection location, and overall appearance reasons.
thanks for any help/ tech advice on this...
-Larry