[MADMIKE]

Called up performanceonline and asked about the MCs in their lineup, all of them are 1". That doesn't sit well with me. Using 75mm or 80mm calipers is going to require an MC larger than 1".

So far this is the hydraulic parts list.

'84 GMC 2500 1-1/4" MC which shares the same fitting sizes.
'72 GMC 2500 Booster, appears to mount the same as the '70 but takes newer MC with a dimple on the piston, rather than the earlier 1.64" recess.
'84 GMC 2500 front hoses. A tad long but we'll see.
'84 GMC 2500 80mm front calipers.
'84 GMC 2500 1-1/16" wheel cylinders.
2- 7/16-24 Female to 3/8"-24 Male adapters(rear drum WCs)

This should keep the bias correct, give better stopping power, and shorter stopping distances. Will probably install an adjustable proportion valve later to fine tune the rear brakes if need be.

Kinda bummed that the aftermarket does not offer a correct disc brake upgrade system. Seems like a lot of cobbled together bits that make little sense.