The modernized LT6 and LT7 engines are expected to ditch pushrods and switch to four valves per cylinder.

Just days after General Motors unveiled the new Camaro ZL1 1LE, a fresh report suggests an even more hardcore Z/28 is in the works.

A development car spotted by spy photographers last year was initially interpreted as a new Z/28, but it now appears to have been the 1LE undergoing track testing at Germany's Nurburgring.

Sources now tell Car and Driver that GM is reserving the Z/28 badge for another new package that could be powered by a new LT6. Engineers are said to have achieved an output of at least 700 horsepower without any help from a supercharger or turbocharger.

The modernized small-block V8 is said to ditch pushrods and switch to four valves per cylinder, with dual overhead camshafts, titanium connecting rods and a flat crankshaft. Earlier rumors suggested the company was working on a 7.0-liter mill for the next Z/28, but the current report points to a 5.5-liter displacement.

C&D speculates the new engine family will spawn a twin-turbo LT7 edition. The various configurations are expected to power the next generation of Camaros, Corvettes and high-performance Cadillacs.

The redesigned Z/28 could surface next year for the 2019 model year. Aside from the impressive engine, the package will presumably bring unique styling and a few extra enhancements to slash lap times.