May be too much work. You can simply fabricate a mount adapter between the carb and the manifold.
A 250 bike carb on a big engine won't run well. It'll probably run, but you'll experience bad choking the moment you ask for more power. I'm running a Toyota 4K carb on a Nissan 1.6 and it only runs to 4k rpm before choking.
Neat trick, that. Wonder if the Toyota 4k was named for that.
