The 1979 Mustang IMSA (International Motor Sports Association) concept is a performance prototype designed by Ford's group, eventually becoming Ford Racing. Elements include large 12 inch wide Gotti wheels, blanked off the grille, hood louvers, rear-facing shaker hood scoop, air-flow sealed headlamp trim, windows flush with outside body panels (the side windows are flip out), ten bulb rear light strip. Under the hood is a 132hp, 2.3L turbo engine. Inside is a dark plexiglass-covered instrument panel, a sport steering wheel, Recaro rally leather bucket seats. Ford built several IMSA Mustangs in 1979 through the 1982 model year.
Source: 1979 Ford Mustang: Ultimate In-Depth Guide. https://www.mustangspecs.com/1979-ford-mustang/
Images: Ford Motor Company
