can anyone tell me what needs doin to a standard 4x4 mt75 gearbox to run upwards of 600 bhp please, or is it a case of swapping for upgraded all together?
and how much is said mod's/gearbox gonna cost?

thanks in advance for any help

 

it's alright, i've just looked on reylands site and answerded the question myself, sorry for wasting the space guy's.