gross horsepower

Chevrolet did not list gross horsepower figures for 1972.

Gross horsepower removes most loads from the engine, including emission controls, before testing.

When the ratings were revised in 1972 to net power output - from the gross horsepower rating used previously - those figures dropped to 80 and 90 horsepower.

That engine has just one more cubic inch of displacement than the six-cylinder '67, but it produces 200 net horsepower, compared with the original car's 140 gross horsepower.

Instead of listing gross horsepower, they had to list the SAE net horsepower which takes into account the power reduction of the accessories and exhaust system.

Gross horsepower was flattering since non-standard exhaust systems were allowed and most of the usual belt-driven ancillaries were removed or discounted from the horsepower calculation.

This was basically a facelifted 541 packing a 361-cubic-inch Chrysler V-8 with 300 gross horsepower, linked to the American maker's responsive three-speed TorqueFlite automatic transmission.

Then, in 1972, the auto industry changed the way it reported horsepower, switching from gross horsepower to a net measurement that took into account losses from necessities like the alternator and water pump.

Catalina Brougham models and Safari wagons came standard with a 400 cubic-inch V8 with two-barrel carburetor rated at 265 gross horsepower that was optional on other Catalina models.

The 425 net horsepower of the modern 6.1 L Hemi makes it even more powerful than the legendary Chrysler Hemi engines of the muscle car era, the biggest of which was rated at 425 gross horsepower.

Engine offerings again included 350 and 455-cubic-inch Rocket V8s ranging from 250 to 340 gross horsepower, all of which featured lowered compression ratios beginning in 1971 to enable use of lower octane regular leaded 91 RON octane, low-lead or unleaded gasoline.

Prior to the 1972 model year, American automakers rated and advertised their engines in brake horsepower (bhp), frequently referred to as SAE gross horsepower, because it was measured in accord with the protocols defined in SAE standards J245 and J1995.

During the 1950s and 1960s Jaguar used the SAE gross horsepower measurement system used by US manufacturers, as otherwise Jaguar cars would have appeared under-powered in comparison with US cars which always quoted their horsepower using the SAE gross system.