Hi M8 R & D's number is 0137872855 the main man is a guy called Roger but you might struggle to talk to him....someone there should be able to give you the infor you require.....the R & D mt75 is a decent piece of kit and I would imagine good for at least 400-450 ib/pounds of torque. I have a contact to have the R & D boxes re-built should you require p.m. me if you want any further info

HTH