I'm not saying it's good or bad, it's simply worth taking a look at

1970 model year Shelby cars were actually unsold 1969 units, given 1970 vehicle identification numbers (under FBI supervision no less)

https://www.autoevolution.com/news/1970-shelby-mustang-gt500-swaps-factory-428-cobra-jet-v8-for-something-even-more-muscular-236480.html#agal_12