[jambo]

GP bikes currently MUST be prototypes (The Harris WCM bike at the start of the 990 era used R1 engine cases and they had to go away until they'd rebuilt it with custom parts). Prototype development is phenomenally expensive. Winning is everything, If a 600 class is born no one is going to try and drop an R6 engine in because they have already developed it, it won't be competitive, legal or suitable. We'll see a new set of bespoke engines from the top 2 or 3 companies, while everyone else does what they can to meet the rules on the budget they've got. In all probability the grid will be decimated to half it's current size.

It's also worth pointing out that the lap times of the SS600's would be mostly limited by the suspension, tyres, and brakes rather than the motor, as all of these would be a much higher spec than on the SS600 race.

Jambo