As someone who owns a 68 Plymouth Fury Sport Suburban wagon and has done the front disc brake conversion using 1973 Plymouth Fury Custom Suburban parts i want to say it was one of the best improvements i have done to the wagon. I used all the parts from a donor car including the proportioning valve & front lines, spindles & lower control arms. I did however use the power disc brake booster from a 65-68 c-body(little hard to find) because the one from the donor was too big & would not fit.
The second improvement i made was replacing the worn steering box with a rebuilt unit from Steer & Gear (614-231-4064 contact Carmine) they manufacture their own gears inhouse to tighter tolerance's than factory get the modern feel rebuild the steering is very tight and able to drive onehanded now with no wandering get their rebuilt pitman arm also. Total cost was $600.00 with core shipped and they have them in stock for immediate shipping. Firm Feel was a 4 month wait & a couple hundred dollars more.
Welcome to the forum great bunch of knowledge people here.