Decision: 5x4 (SBP) or 5x4.5?

I have both patterns in manual disc brake. The 67 Cuda has 11.75 pin discs up front and 11 x 2.5 drums with a custom, shortened, 4.50 BP 8 3/4 in the rear to keep the original track. It works real nice. But, if I had to do it again, I'd stick with the Original K-H 5 x 4.00 front discs. They work well and they are lighter. The A Body 8 3/4 only came with 5 x 4.00 pattern. The 68 and 66 formula S have the original K-H 5 x 4.00 BP front discs with the 10x 1 3/4 rear drums. All original, Done.

I don't see the point of rear disc brakes.