Absolutely the wrong engine to put in a Bike Engine'd Car.
It's too fragile. You want a small piston, low stress I4, not a huge piston, high performance engine pushed to the limits of metal technology. A car will put way more force stress on a bike engine, than a motorcycle ever did. The reason a BEC isn't a dog with such a small engine, is because unlike the bike, the car can put down 100% of the power to the ground immediately. That's hard on the engine, and especially the bike trans.
'Busa engines are stressed out pretty hard in Lotus 7 kit cars. But you get the engines from salvage bikes, so it's not a big deal to replace them every year. A full bodied car sounds like a nightmare.