disk brake kit

Ha!

That MBM kit is pretty much just a 73+ A-body disk kit. Looks like they machined down the center register and are buying blank rotors to add the 5x4" pattern to. Might be wrong about how they're doing the rotors, but, those are definitely 73+ spindles, calipers, and caliper brackets. That's why they include an adaptor kit for the spindles, they're for large ball joint UCA's so they include a set of tapered sleeves like the one's Dr. Diff sells.

All the challenges of using the 73+ disks on a SBP car without the benefits of actually converting to BBP. You still have to deal with the wider track width, you still get tapered sleeves to use the spindles with the SBJ UCA's (or you could get the later BBJ UCA's), and as an added bonus most of the SBP wheels won't fit because of register or backspace issues. At least if you went BBP then stock 14" BBP wheels would fit. Did you have 10" drums originally? Because it says right in their instructions the kit won't work if you didn't have 10" drums up front.

Seems like all the SBP disk conversion kits out there are a problem. The Wilwood's have an excessively large register and won't work with stock SBP wheels, the SSBC kits seem to have several threads going on issues, and the MBM kit is really just a 73+ BBP disk set up with redrilled rotors. Good grief.