Aftermarket for duratec...

It's a version of the Duratech, yes, but with Mazda-designed heads with variable valve timing (S-VT).
 
Just for clarity's sake:
The 3.0 liter V-6 offered in the Mazda 6 is a Ford Duratec block with modifications by Mazda as pointed out by mts3.
The 4 cylinder offerings are Mazda sourced and designed. The MZR series will become the standard for the entire Ford group. You can expect to see versions of this engine in the next Protege (Mazda 3) and the next Ford Focus, which will share a platform.
 
Correction 2.3L I4 Mazda 6

The 2.3L I4 is a Ford Motor engine shipped to mazda. It's made at Dearborn Engine Plant, the engine is the same as the Ford Ranger.
 
Correction of the correction

From the CarsEverything preview of the Mazda 6:
Mazda Motor Corporation's new family of 4-cylinder engines is the latest in a new range of powertrains that will establish Mazda as Ford Motor Company's center of excellence for all large I-4 gasoline engine development. The new engine will be used in a broad range of vehicles, beginning with the Mazda 6. It will be offered in three displacements: a 1.8-liter, 2.0-liter and an advanced 2.3-liter with Mazda's Sequential Valve Timing (S-VT), which improves performance efficiency, and balance shaft to eliminate vibrations resulting from free mass and momentum forces.

The Mazda MZR engines will be built at the AAI plant in Dearborn. But that is a joint Ford/Mazda plant. They will be used in the next generation Protege (Mazda 3) and the next generation Focus, which will share a common platform. They will probably be used in 4 cylinder truck applications, as well as car applications. The point is, it will be built in Ford plants and Mazda plants, but it is a Mazda design from the ground up.
 
Back