Since the Pinto is a unibody car, the kit probably just used the Pinto suspension. The 74-80 Pinto front suspension is very popular with the street rod crowd. To determine the year used, look at how the rack is mounted to the chassis cross member. The 74-80 use large horizontal bolts, one on each side. The 71-73 use a strap with two vertical bolts on the passenger side, the driver side mounting varied. Have fun with the kit. Would like to see photos.
In the mid 70's, there was a company in North Miami making kit cars using the Pinto suspension, drive trains, etc. They would buy new white Pinto's for the parts (guess cheaper than buying new components). Never tracked down where the bodies went but did see a car hauler load of them heading north on I-95 one day.