Well, concidering the fact that even a stroker engine will run 50,000 on the street very easily if you dont scatter it, I would say either MIGHT be a good choice. It depends on your plans. For the street in the 400-450 HP range I think the will be fine. Try to push 500 or more, and the cylinders will surely split unless grouted. If tall grouted, the streetabliliy becomes seriously limited.