I have done the 4 wheel drum to power disc brakes and drums in back conversion twice.

All the components are different between 4 wheel drum and front disc. You need to acquire all the parts for disc brakes to make it work correctly.

The valves, lines, master cly are all different, do not mix the different parts together and expect good results because it won't work like it should from the factory.

The lines are different from drum to disc.

You must decide whether you are going to use early or late disc brake valving because that affects your line choices. and like shown above there are 2 different early setups too, do not mix them.

Keep it all factory and they will fit/work flawless, it you mix them then you will have all kinds of trouble making it work.

I know it is very confusing and contributes to people getting the wrong parts the first time from many venders, not really the venders fault.

You can use the late(72-74) model proportioning valve on your 70 model as they are going to be easier to find I think. I would use all original used valving verses new. But keep it all the same. ie: 72 or 70 do not mix like said twice. That is when folks get in trouble by mixing components then blame the line guys for your errors.

I have bought a lot of Fine Lines stuff for 3 different cars and the fit is great. Know what you need and they will bend it perfect.