63 Valiant - rust in front A-arm mounts

Waffling, so need more information...sorry!
@Oldmanmopar , I confess, the result on yours sure looks good! I just don't know if I've got the place to do it...regular two car garage. How do you get the frame clip off the crossmember and body at the firewall without destroying them? They look stamped tight and welded (photo of mine), but could be rivets, filled bolts under the paint, I don't know...

So, if I go this route:
finish taking off suspension...
Strip old clip (sheet metal, radiator, etc)
drop engine/trans in the cradle
Lift car with engine hoist so engine/trans can be pulled out of the way?
Pull off the old clip, put on the new one (just welded, or what)?
Put it all back together...

Also, you're close, in PA...know of any yards or anybody with spares/donors in the region that might have a good clip?

Just trying to figure out the best way to save her...thanks!
Steve