[Mark IV]

The rule requires a certified engine, this doe NOT mean it will be a "certified crate engine" but it can be a "piggyback" certification i.e. the powertrain from an current production vehicle. We used this to EPA the AC MK IV, it was the Mustang 5.0 powertrain and as long as the weight was within a percentage (or less) and the ratios were within an allowable range you could certify with a simple tailpipe test and the evaporative "shed" test. So the fact that GM has certified crate system has no bearing on using a Coyote or an Ecoboost in a certified replica.