Field also backed the construction in 1980 of an Interscope chassis designed by Roman Slobodinskij for the Indianapolis 500. This was intended to take a turbocharged six-cylinder Porsche engine (similar to the one Ongais and Field were using in their Porsche 935) but a dispute with USAC over turbo boost meant the program was abandoned. The car was eventually fitted with a conventional Ford Cosworth DFX engine and entered in the 1981 500. Ongais led the race but crashed and was critically injured. In 1982 a recovered Ongias gave the car one last start at Indy but that too ended with an accident.