It has been awhile. As I recall, I believe the
GSXR1100 engine fits into the
GSXR750 frame. The frame is the same and because the engine cases are the same size, just bored to a larger diameter in the 1100, it is an easy engine swap.
But I think there is a
difference in the lower engine that makes it not possible to put the
GSXR750 into the
GSX600 Katana frame. It may be that you need to fabricate new lower frame rails to accommodate the larger GSXR engine.
Your best bet is to check with the
discussion forums at DragBike.com. It has been my experience that anyone who has successfully accomplished this engine swap, would be more than happy to share their knowledge and steer you in the right direction.