Pikes Peak Hill Climb, dual engine setup

Hello, an Acquaintance of mine is Jim Willy's brother, according to him a number of years back his brother made a dual engine car (one in front one in back) and because of that was able to far outdo everyone else that year. Including passing 2 other racers.
Supposedly the year after this multi engine vehicles were banned, and the rule gained the nickname Jim Willy's rule.

What I'm wondering is if anyone has any information to support this or refute this claim, and or if anyone has just general information.