The Toyota MZ engine family is a piston V6 engine series. The MZ series has an aluminium engine block and aluminium alloy DOHC cylinder heads. The cylinders are lined with cast iron, and is of a closed deck design. The engine is a 60 degree V6 design. It uses multi-port fuel injection (MFI), four valves per cylinder, a one-piece cast camshaft and a cast aluminium intake manifold. The MZ family is a lightweight V6 engine of an all-aluminium design, using lighter weight parts than the heavier duty VZ block engines in an effort to lower production costs, decrease engine weight, and decrease reciprocating weight without sacrificing reliability. Toyota sought to enhance the drivability pattern of the engine at exactly 3000 rpm, since that was the typical engine speed for motors cruising on the highway. The result was less cylinder distortion coupled with the decreased weight of rotating assemblies, smoother operation at that engine speed, and increased engine efficiency.

The Toyota GR engine family is a gasoline, open-deck, piston V6 engine series. The GR series has a 60° die-cast aluminium block and aluminium DOHC cylinder heads. This engine series also features 4 valves per cylinder, forged steel connecting rods and crankshaft, one-piece cast camshafts, a timing chain, and a cast aluminium lower intake manifold. Some variants use multi-port fuel injection, some have D4 direct injection, and others have a combination of direct injection and multi-port fuel injection or D4-S.