Definately a interesting subject, to my knowledge Yamaha FZR1000 (Rocket), Honda Blackbird, Kawasaki ZX12/ZZR1100 and Busa engines have been used in a variety of cars. There have already been a couple of twin engined attempts with Kwack engines I think.
How about a V8 from two Busa engines? Now that would FLY!!
Back in the 1980’s Yamaha RD500 engines were used in some specialist hill climb cars. I think the RG500 too but I am not sure.
They have been bikes with car engines, usually American Chevvy V8 or the Rover 3.5 V8 (itself an old Buick design). Though these are usually heavy and cumbersome to ride and seem a bit pointless to me.
One mad Aussie even loped 2 cylinders from a WW2 Rolls Royce V12 Merlin engine that had seen service in a Mosquito Fighter Bomber, and made a huge V twin bike. Made the front cover of “Bike” magazine in 1986.
Hope you find the time to make the project ID.