hey sorry to hijack, but we are the australian dealer for jerico transmissions and they will handle all the power you could ever make with an SR and for a gearbox with any ratios you can think of to bolt straight in to an SR is around $6500 and is full dog box REM polished gears and will be indestructible no matter what you do so that oppurtunity is out there. there is also the superduty box more expensive but can handle well over 800hp all day long if interested pm me
Also you can lift the box in one hand super light and they fit RB's too, there 4 speed but you don't need 5 gears on the track you just run diff ratio to suit our AU V8SC runs fine with a jerico