Well, two things.
One: My frame only has some surface rust here and there. 28K miles, none in winter, garaged 24x7.
Two: My ticking clock is getting a little more serious. I don't have the physical capacity to do things compared to just 3 years ago when this started and I need to get this thing done. Plus my 67 "driver car (??)" needs some attention that I will only do in the shop. I think both mains are leaking along with the DS pan gasket and either the front seal in the transmission or something more serious.
So get the 87 done more per the original suspension and brakes project plus - new bushings and rear end. Tick-tock-tick-tock. Swap cars. Pull motor/transmission from the 67. See what version of 425 I have and how serious? I guess popping the intake is the only way to know for SURE? Find transmission leak and how serious? If I have a 39 degree 425, I will likely re-cam it while out and put on a Performer intake. If 45 degree, will just fix the leaks and drive it. If I discover it has more serious surprises, I may build up the 400 that belongs in it? Tick-tock-tick-tock!