I am currently working on my '64 Tempest and want to upgrade from a single-reservoir m/c to a dual. I found a manufacturer who makes a "bolt-in" replacement set-up consisting of: mastercylinder, pre-formed lines and, new distribution block. Supposedly the new distribution block bolts up to the existing front and rear lines. I have everything loose except for the last flange nut on the distribution block. I have been letting everything soak in PB Blaster for a week and impacting the nut slightly using a hammer and flat-tipped punch. I have the correct flange nut wrench but I am afraid of breaking something if I apply too much pressure. I am also a little leery of using heat for fear of distortion. Any suggestions?