I'm fairly certain the kit details reveal JoHan was close to a deal with ChryCo, but got left at the altar at the last moment. Or, they just decided to one-up MPC, skipped the annual kit, and produced a true 'stripped out' race car, promo contracts or no.
IMO, the best-ever E- platform body in scale, slaps Revell right in the kisser (save for the headlight/taillight detail, up to '70s standards but not todays.)