April 1, 2019 – Fiat Chrysler Automobiles announced this morning that it has entered into partnership with Mitsubishi Motors to revive the Diamond Star Motors nameplate, which was extremely popular in the mid-1980s through the late-1990s. The DSM brand is largely known in performance circles for its vehicles powered by the legendary 2.0-liter turbocharged 4G63 engine, or the stout 6G72 twin-turbocharged 3.0-liter V6.

Hoping to live up to that same legacy, the new DSM venture’s first project is a turbocharged 4.1-liter inline-six with the legendary HEMI combustion chamber and cylinder head design, which will be flex-fuel capable. While details are scarce, an inside source told us that the cylinder head would bear close resemblance to the Apache heads on the 6.4L variant of the Gen-III Hemi V8 engines, but with two additional cylinders added to it, and dual overhead cams.

The dual overhead cam arrangement will feature variable cam timing on both the intake and exhaust cams, along with variable geometry within the intake runners, to switch from long to short runners under preset conditions, to maintain low-end power, while still being able to rev to the moon.

It will reportedly be a WAY overbore engine, with a 4.215-inch bore and 3.00-inch stroke built to take upwards of 25 pounds of boost from the factory 76mm turbocharger. In order to live, the iron block will be filled with a first-ever from either company – an OEM billet steel crankshaft and connecting rods, with forged 2618 pistons.

The cylinder heads will feature the HEMI’s dual spark plugs, single intake and exhaust valve, and killer port design, modified for the overhead cam arrangement – both of which will feature variable timing control (under Mitsubishi’s MIVEC nameplate). The engine will also feature a variable-geometry intake manifold to help the engine perform in the low-RPM range on the street. A leaked internal document that was shared with us by our contact shows that DSM wants to rival the Honda S2000 for the factory rev-limiter settings, and an 8,000-rpm-plus factory limiter isn’t out of the question.

When asked for official comment on the new engine, FCA’s representative said, “What is this, an April Fool’s joke?”

Happy April Fool’s Day!