DENVER (AP) — When Kevin Erickson fires up his 1972 Plymouth Satellite, a faint hum replaces what is normally the sound of pistons pumping, gas coursing through the carburetor and the low thrum of the exhaust.

Even though it’s nearly silent, the classic American muscle car isn’t broken. It’s electric.

Erickson is among a small but expanding group of tinkerers, racers, engineers and entrepreneurs across the country who are converting vintage cars and trucks into greener, and often much faster, electric vehicles.

Despite derision from some purists about the converted cars resembling golf carts or remote-controlled cars, electric powertrain conversions are becoming more mainstream as battery technology advances and the world turns toward cleaner energy to combat climate change.

“RC cars are fast, so that’s kind of a compliment really,” said Erickson, whose renamed “Electrollite” accelerates to 0-60 mph (0-97 kph) in three seconds and tops out at about 155 mph (249 kph). It also invites curious stares at public charging stations, which are becoming increasingly common across the country.

At the end of 2019, Erickson, a cargo pilot who lives in suburban Denver, bought the car for $6,500. He then embarked on a year-and-a-half-long project to convert the car into a 636-horsepower electric vehicle (475 kW), using battery packs, a motor and the entire rear subframe from a crashed Tesla Model S.

“This was my way of taking the car that I like — my favorite body — and then taking the modern technology and performance, and