a great old topic Joe but methinks your numbers are low.
Back then, the Cleveland powered Pro Stock Fords (not just Pintos) were so strong that my bro' and I looked forward to each month's newest Super Stock and Drag Illustrated, Car Craft and Hot Rod magazines. It seemed that every chassis shop, not just the big names like Wolverine, Don Hardy, etc. had Pintos on the jigs. Heck, as it turned out, the Pro Stock revolution actually made Wolverine and Hardy big names in the sport as they were small potatos before then. Folks like Wisconsin's R&B Chassis (Ron Buttera), Detroit's Logghe Bros., S&W Race Cars in PA, and on the left coast Don Long (funny car/dragster builder) were all allegedly involved in building the chassis if most often not the entire car.
Back then, it wasn't unusual for racers to buy a shell (body-in-white as it came to be known) right from Ford, acid dip it in a backyard pool, and then bring the unibody to a chassis shop. There, the actual builder (if not Wolverine or Hardy) may have purchased a pre-bent moly pro-car kit from Hardy (these were big sellers btw) or bend up their own tubing. Most cars left the chassis shop unfinished with but with tinwork. The racers hung all the glass panels, plexi windows and had the car painted by local talent.
Btw, what drove so many racers to the Pinto was Ford's loud and clear proclamation that they would sell anyone a shell. I'll try and find one old article that speaks of this.
http://www.oldhippie.com/forums/ford-mercury-lincoln-forum/97-early-pro-stock-fomoco-3.html