For instance, the oil and water pumps are unique to the ER27,[5][6] sharing similar bolt patterns and design to the EA82,[7][8] but being of a higher flow in both cases.

[9] The intake manifold uses a two piece design with a lower section bolting to the heads containing the coolant bridge, injectors and various vacuum lines.

[1] The EG33 was exclusively fitted to the Alcyone SVX, where it was paired with the 4EAT automatic transmission in both front- and all-wheel-drive configurations.

Unlike the SOHC EJ22 it shared some dimensions with, the EG33 featured dual overhead cams; both engines used four valves per cylinder.

[28] The EZ30 was refreshed in 2003, and when the Tribeca was introduced for the 2006 model year in January 2005, the EZ30 II was the sole engine option.

[35] Unlike prior Subaru flat-6 designs, the EZ30 has a significantly smaller bore pitch (the distance between adjacent cylinder centerlines on each bank of the engine block) than the contemporary flat-4 EJ-series.

These changes resulted in a more compact block; the external dimensions of the EZ30 are similar to the EJ25 four-cylinder engine, with length increasing by less than 1 inch (2.5 cm),[35] allowing for easier fitment in existing vehicles.

[44][41] Other detail improvements included a new block casting and a reduction in overall weight by 8.91 kg (19.6 lb), achieved through the use of hollow-journal camshafts, reducing the number of bolts in the timing chain cover, and switching to a plastic intake manifold.

A change to the cam drive resulted in an engine that was slightly longer than the preceding EZ30 by 0.83 in (21 mm), but maintained the same width.