'05 or '06 Mustang 6 cyl. in Stock?

[Bill Harris]

It's up to the MFG to provide all the necessary data for the engine(s) to NHRA so that the car/engine combination can be classified and verified in a tear-down. If the MFG doesn't give all the information for a particular engine, then you can't run that engine in stock or super stock. NHRA doesn't go looking for the data if it's missing.

For NHRAs part, they factor the HP for competition according to rules known only to aliens from some other galaxy, or perhaps by one of the many gods worshipped by the masses.

You can request that FoMoCo provide the necessary data to NHRA if you want to pursue that path. Ford Racing has been very active recently so you might be able to get them to fill in the blanks on the engine specs so it can be run. Its new enough that it probably wouldn't be a big deal for them. Evan Smith might be able to point you in the right direction.