[KensRedZed]

A question for our friends across the pond ?
I believe that muscle cars of the 60's and 70's used 3litre or higher capacity engines, but is it a characteristic of ALL muscle cars ?
Were there any under 3litre capacity motor muscle cars ?

I decided to revisit the original question.

GM tried to make a small muscle car. But it was quite the failure because it lacked power. It was not really a muscle car. Just something rare and different. At only 110 horsepower, my Z-28 Camaro would have eaten it for a snack.

The Cosworth Vega was nothing to be proud of. For the money, everyone that bought one wished they had bought a Corvette instead.

From Google:
The 1975–1976 Chevrolet Cosworth Vega was a limited-production, high-performance hatchback featuring a 2.0L inline-four engine with a twin-cam, 16-valve cylinder head designed by Cosworth Engineering. It was designed to create excitement for the Vega line, featuring a black-and-gold, F1-inspired, color scheme, enhanced suspension, and electronic fuel injection. Despite its advanced, hand-built engine, only 3,508 units were produced due to a high price point (near a Corvette) and emission-restricted power, making it a rare, collectible vehicle today.