I don't think that the SP gearbox wil fit in the Thundercat engine seeing as they have a complete new and improved drivetrain compared to the FZR's. The SP gearboxes do however fit one on one in the 600R cases and with a two different bearings they wil also fit in the 1WG/3HE cases.

But don't know if a 400 gearbox can take the 100+ hp's. It is gonnan be a roadbike and i dont wanna end-up with an undrivable bike on the open road. If it was gonna be a track bike then i wouldnt hesitate.

The hyperthetical 720 engine in the thread is FZR600 cases and crank with T'Cat top end ... so the SP gearbox should fit. The Sp has a high 1st gear which needs some extra revs to get off the line, but with the extra cubes will come mid and bottom end power so it shouldn't be to difficult. It should help to keep the front down too.

Second gear on T'cat was a touch weak anyway ... so you can pick up a T'cat engine that jumps in second for about £100 off the Bay

Evilchicken0 wrote:The hyperthetical 720 engine in the thread is FZR600 cases and crank with T'Cat top end ... so the SP gearbox Second gear on T'cat was a touch weak anyway ... so you can pick up a T'cat engine that jumps in second for about £100 off the Bay

'Cept that shipping to the Netherlands would be about 3 times as much...

there's bound to be T'cats over there and somebody will have sh4gged a gear too

oh the 88bhp is just a 600, not a 660. I'd say a 660 would give 93-94bhp and a big lump more torque due to long throw crank. But i want it where I have to detune the engine slightly so i can run loads of torque from really low down so i'll be able to match the big bore sv's off the corner. Hence 727cc

Just had my 4/6 on the dyno. Its a totally standard 600 from a 95 fzr600r, using the 400 airbox with a k&n filter. It was giving 87 hp at the back wheel. Wont be staying sandard for long though!