So I was thinking more about the IX tonight. I love the VIII because it has a proven engine and lots of development time. I understand the IX just has a new head, but are internals like valves/springs/pistons/retainers/cranks/etc. going to be able to fit no problem into the IX? I know it is early but it is a big consideration. Does anyone have experience with this?

Thanks.

EDIT: I guess the better question is to ask what is known to NOT fit from engine to engine. I know that the intake cam is a no-no thusfar.

 

Indeed, Bump to this question. Because i do plan to take my IX up over 600HP in the near future but i am unsure what will work and what wont work, a race head for instance.