IF THE SAME VALVE BODY THAT IS IN THE CAR is fitted with a brake and reinstalled there will be no change in rpm in theory.if you install the 442 trans in the gn itll work great but you must retain the original gn governer . it is slightly lighter than the 442 although the 442 has a 3.73 final drive ratio. our electric brake requires removal of the trans.the manual brake does not.either way if the trans oil is dirty we wont install either unless the customer understand we take no responsibility for clutch failure.this is due to the extra stress imposed with the brake.want one?give a call and make an appointment wed be happy to install it.ELECTRIC BRAKE INSTALLED 900 ,MANUAL BRAKE INSTALLED 400.