There are a wide range of engines that will fit, the vauxhall seems to be the most common conversion, and fits quite well without too much major work.
The only downside is the engine is quite heavy, and having the extra power does tend to do quite a bit of damage to the driveline.
IMHO a 1600 vit engine and a decent carb would be a better choice, unless you have plans to upgarde the axles.