i have a stock brake component 73 240z(booster, master, proportioning valves), i have the toyo fornt brakes and the 240sx rear disc. right not pedal pressure in the front is hard...and the rear discs aren't even clamping...i assume this is due to the fact that the 240 proportioning valve is designed for the small cyliner for the drums...and won't allow the necessary fluid for the larger piston on the sx caliper. is there a proportiong valve off another Z that i can use for the rear, or can i T the lines at the valve on the firewall and run the wilwood in line with the rear brake line?