The AC engines won't do too well in a car or truck, they don't have the RPMs that car engines do (they're only about 1/2). They will probably run hot as well, AC engines use the prop wash to stay cool. With that said, if you do try it, you will have to make/modify just about everything.
AND ill guess the cooling fins will be to close to let air pass. just a guess. thats why you dont put small air craft engines in street cars. it MIGHT work on a drag race car???