If you use the genesis spurs, you will be lowering the gearing very slightly. That, along with the fact a big blosk generally wont rev as high as a lil fella, means your top end may well be down. But torque and off the line performance will be mental.

Might be worth looking for Hyper 10 clutch bells and gears. I think they go to quite high tooth counts and ofnas gears are hard as hell. That might get your top end silly and still give low end performance reliably... maybe...