I have a friend who rebuilt his 64 nova break system and put in Dot 5. He ran that for 150,000 and never had another break cylinder or master cylinder service. Dot 5 is not hydroscopic (absorbs water). I am going to use dot 5 in my 46 system that is a total rebuild. DOT 3 fluid absorbs water and this is what causes the rust and corrosion in the systems. I know you cannot use DOT 5 in modern cars due to seal issues.
