hello , i have a 1939 chev truck 1.50 ton , i have updated the rear end from a 1990 Apollo motor home with disc brakes . the front brakes are still the original drum brakes , i have replaced the single master cylinder with a dual output master cylinder . many people state that a proportioning valve needs to be installed in the brake lines . with the drums up front and disc in the rear where is the correct placement for the proportioning valve on my system ? all articles i have read are for disc brakes up front and drum brakes in the rear and mine is the opposite . thank you 1pete1
