The GM High Feature engine (also known as the HFV6, and including the 3600 LY7 and derivative LP1) is a family of modern DOHC V6 engines produced by General Motors. The series was introduced in 2004 with the Cadillac CTS and the Holden VZ Commodore.

It is a 60° 24-valve design with aluminum block and heads and sequential multi-port fuel injection. Most versions feature continuously variable cam phasing on both intake and exhaust valves and electronic throttle control. Other features include piston oil-jet capability, forged and fillet rolled crankshaft, sinter forged connecting rods, a variable-length intake manifold, twin knock control sensors and coil-on-plug ignition. It was developed by the same international team responsible for the Ecotec, including the Opel engineers responsible for the 54° V6, with involvement with design and development engineering from Ricardo plc.^{[citation needed]}

GM's Australian auto division Holden produced a HFV6 engine under the name "Alloytec."

The HFV6 was designed, tested, and produced in a joint program by Holden and Cadillac.^{[citation needed]} A majority of designs into the new alloy construction, transmission pairing, and first use in production were all undertaken in Detroit (and manufactured in St. Catharines, Ontario). Holden was charged with developing smaller engines (Holden 3.2 LP1 and Saab 2.8 Turbo LP9) as well as their own Holden 3.6 and 3.0 HFV6 (called the Alloytec V6) for local models.

Cadillac and Holden both tested variations of these engines in the United States and Australia.

A 2.8 L (2,792 cc) LP1 variant was introduced in the 2005 Cadillac CTS. It was also used on the Chinese 2008 CTS. It has a 89 mm × 74.8 mm (3.50 in × 2.94 in) bore and stroke, sequential multi-port fuel injection and a 10.0:1 compression ratio. The LP1 was built in St. Catharines, Ontario.

Applications:

This engine is also known as a A28NET, Z28NET, Z28NEL or B284.