Rear brakes lock up, front factory disc 67 Barracuda

Thanks Dan, I have the 11X2 1/2 on my 67. They will lock up earlier and althugh they haven't been a big problem I'll change over the wheel cylinders this winter, and fill with new brake fluid. What's the best to use? I have 73 disks up front and 11 X 2 1/2 in the back. The splitter is from the 73 disk car with 10" drums.