After two years using a Len Terry design, Anglo American Racers (AAR) employed Tony Southgate to design the 1968 Indy Eagle. The Mk4, designed by Southgate featured a lower, flatter monocoque, and changed from the Lotus-style rocker-arm suspension used by Len Terry on the earlier Eagles to the outboard springs and wishbone suspension still favoured by Lola and Brabham. Five 1968 Eagles were ready in time for the 1968 Indy 500 with several different engine options. Bobby Unser won the 1968 Indianapolis 500 in the Leader Card Racers example, powered by turbocharged Offenhauser. The car entered by Lindsey Hopkins for driver Roger McCluskey also used turbo Offy. Gurney’s own car being fitted with the stock block Gurney Weslake Ford, Danny Hulme’s having the quad-cam Ford V8 Indy engine, and Tom Friedkin’s entry for Jerry Grant risking the unproven turbo Ford. A sixth car, a road-racing version fitted with a 302 ci Chevrolet engine, was acquired by Roger Penske, and Mark Donohue raced it at Mosport and Riverside that season. In his Sunoco-sponsored car Donohue was sixth in the first race at Mosport, and improved to fourth in the second event same day. At Riverside Donohue retired early with broken right front wheel suspension.
|1968||USAC National Championship||Rex Mays 300 Riverside|
|Mark Donohue||12||Roger Penske|
|Eagle Mk4||Chevrolet||Sunoco Eagle|