When the Bockscar was a Streamliner, we used a 440cc Xenoah snowmobile motor and a Mac 10-10 Chainsaw motor to bring it up to size. Used the Mac to spin the Xenoah for start, and ran both dual throttles... but Lakesters can only have 1 motor... when Bockscar became a Lakester in 1984, we put a 750 Honda Interceptor motorcycle in it... no not just the motor, we put the motorcycle, frame, motor, swingarm... basically everything from the triple tree back except the tank, seat and fender in the car.
So yes, most use motorcycle motors... some all the way to G class.
PS read the rules before you buy a SCCA formula 600 car to run at Bonneville.