Turbocharged Desoto hemi for 67 Valiant

What do you make your molds from and how do you shape it? I've had some experience with composites.
The car is a 67, but I got a 69 hood and grill assembly. The 67 has an assembly running down through the grill assembly that holds the hood hold down. That gets in the way of the intercoolers. No room for the tranny cooler, so I got a glass bumper and the cooler will fit in the bumper.