I believe the wheels were made by Western Wheel in Fresno Ca. I had a set on an E150 back in the seventies. They were bought out and are now called Western Chrome.Their web site shows wheels for big rigs. I hope this helps. lastchance
Even though they are 4 lugs, they were probably true Shelby (aftermarket) rims. You wouldn't believe some of the hokey stuff Shelby put his name on during the 70s! Some of the stuff I have seen, it wouldn't surprise me if he offered mudflaps at one time. Seriously, that kind of accessory stuff is what he was reduced to when the dark ages hit. Dave