Lotus 56b. Lotus wanted one car to run both series, Indy and F1. It turned out a bit too heavy for F1 but they ran three races with it in '71 and the only points paying race it ran was the 71 Italian GP at Monza. Fittipaldi finished in 8th with remarkably little video to be found of it! Inboard brakes and all wheel drive. No wonder it was heavy.