Factory disc question for those with stock disc brakes. NOT aftermarkets

MoparLeo said
I am going to assume that the brake system on a 1963 vehicle uses an single line m/c .
And being a 62 year old car, all of the brake lines hard and soft need to be replaced.
This when you get all of the brake lines plumbed properly.
Using vintage parts on a brake system is asking for it.
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That doesn’t make a ton of hydraulic sense to me.
The hoses are all new. The hardlines were working fine with the drums and are the same size as disc systems. The fluid runs clear when bleeding.