Input (grade 13): The Ilmor Mercedes V-8 engine, also a mainstay CART powerplant, was permitted, but the only time it was used was a one-off at the 1996 Indy 500 by Galles Racing.
Output (grade 4): The Ilmor Mercedes V8 engine, was allowed. It was only used once at the 1996 Indy 500.