Reply to "Brake line pictures."

Its true that increasing the size (or number) of calipers will require a larger master cylinder to deliver twice the volume of fluid, or your pedal will be on or near the floor in hard stops. One friend got carried away and put 6-piston fronts & 4-piston rears on, and could not completely stop his Pantera (with a stock master) before the pedal hit the floor.

You will need a manual proportioning valve (but definitely NOT the stock one!) to re-balance the system, once everything is plumbed leak-free with new flex hoses. In the rear, there are a number of hydraulic calipers that can work (with adapters) but try to find a pair that have built-in e-brakes so you don't have to re-engineer the e-brakes. Leaving them off may get you in trouble with insurance adjusters or yearly inspections (if applicable in your State). Hall used to sell adapted GM Z-28 rear calipers with integral e-brakes.

I successfully use a pair of mechanical e-brake calipers sold by Wilwood that can be made to work well with stock Pantera cables and handle, but they are a sliding-type aluminum caliper that requires a fabricated bracket. Pantera East used to sell this caliper (with a different bracket) for Panteras and Vipers, and they may still be available; call Marino Perna in FL to check.