I have been using DOT 5 in my 40 for past 20 years with zero problems.
If you don't drive your car a lot, I recommend it. Read all about it here:
https://www.google.com/search?q=does...hrome&ie=UTF-8
and
https://www.fordbarn.com/forum/showt...ne+brake+fluid
Also, do a Fordbarn search on Silicone brake fluid.