SBP or BBP?

If you had Kelsey Hayes discs and an 8 3/4 with the SBP, I see no reason to switch. 10 inch drums are also OK. You probably have 9 inch drums, so I would definately switch them ASAP. I'd also factor in a front sway bar while you are at it. I have cars with both. Both disc systems work very well. To me, it depends on what you can get hold of and how much it costs. I only run factory systems, sway bars and all. I'm not up on what sway bars are available for our early "A"s with the BBP.