From '73 to '78, Ford fullsize cars used a bit of an oddball lug pattern...5 x 5". Hence the reason Ranger wheels wouldn't fit, and neither will truck wheels.

Your choices for finding factory wheels at the local yard are limited. Aside from finding a fullsize Ford car, I THINK the Chevy Astro had a 5 X 5" pattern...but that's just heresay. Oh, yeah...the '72-'79 midsize Ford police cars used that pattern too, if you happen to run across one...

Pat