Recently i upgraded the brakes on my 71 chevelle to a 4 piston wilwood setup front and rear. I installed a 1" bore wilwood master cylinder and a wilwood adjustable proportioning valve. The car stops much better now but i am having a issue with the rears getting very hot. I triple checked the parking brake and even went as far a taking it completely out of the question but it did not help. I have the proportioning valve set to the lowest setting for the rears which is suppose to be 57% incoming pressure. Does anyone have any thoughts on what else could be the problem. Also it does have a new brake line going from the frame to the axle and i know it is not collapsed. Thank you in advance for any input