Frenchman Guintoli, 41, last raced in MotoGP in 2019 as a wildcard and test rider for Suzuki, but has stayed active in motorcycle racing with the Hamamatsu brand's endurance racing programme.
Alongside Yoshimura SERT team-mates Gregg Black and Xavier Simeon, he won the Le Mans 24 Hours motorcycle race in 2021 and scored a second triumph at the Circuit de la Sarthe the following year.
Guintoli, who also won the World Superbike title for Aprilia before joining Suzuki in 2017, revealed via SERT sponsor Motul that the idea of transitioning to car racing came up after his second Le Mans win.
"I think we were drinking some champagne after winning the 2022 Le Mans race and discussing and joking and I thought, 'actually, this is not a bad idea!'," said Guintoli. "Since then, I can't stop thinking about it.
"I want to try and be the first person in history to win the 24 Hours of Le Mans on both motorcycles and cars. This is now my challenge.
"I think it would be an amazing story if we could do it. If you don't dream big, you don't achieve anything big."
Guintoli drove a Volkswagen Golf TCR at Silverstone last November in the Birkett Relay club event, and has now forged a partnership with Radical as he seeks to gain the experience necessary to race at Le Mans on four wheels.
"The idea is to enter the new [LM]GT3 [class] with the new regulations from 2024, or maybe 2025," he clarified. "I want to be a very good bronze[-rated] driver because I have very little experience of racing cars.
"If I practice a lot and become very good, then there may be a chance to enter a different category. But the Hypercar category I think will be very difficult."
Should he succeed in his ambitions of racing at Le Mans, Guintoli may not be the only ex-MotoGP racer on the grid, as seven-time champion Valentino Rossi has targeted a debut in 2024 after switching to car racing full-time in 2022.
Rossi has already tasted success at La Sarthe on four wheels as he and team-mate Jerome Policand scored victory in the Road to Le Mans support race last month in their WRT-run BMW M4 GT3.
Guintoli remains active in bike racing this season and is gearing up to contest the Suzuka 8 Hours next month with the Yoshimura SERT squad alongside Black and Etienne Masson.
