Originally Posted by Prot

There is a point where when the bore exceeds a certain size, you have to bore the cases. The large bore engines have reinforced cases. If you exceed a certain bore size on a stock HD case, it becomes weak. In my opinion it is ok to go a little larger on a stock case, but then after that, if the intention is to stay with a stock case, your efforts are better spent on better flow in and out, better fuel system, etc to get the most out of the displacement you have.

Generally a longer stroke engine will turn less rpm's but will have more low end torque. That principle is what Harley engines, especially shovelheads and Evo's are designed on.

Japanese bikes, especially crotchety rockets use very short strokes with a larger bore. They have five digit redlines. They tend to produce more high end horsepower and less low end torque.

I may be wrong, but I think TC88's use a larger bore and shorter stroke than Evo 80". That is part of why they lost the characteristic sound and feel different. The TC96 and TC103 may have rectified that but I am unsure.