Thanks for the comments guys. I think you could wear a space suit made out of asbestos and still get the hot potato welding galvanized! GA asbestos isn't good to breathe, but it is one hell of a fireproofing! And all around us, its amazing how much they made.....its still everywhere.
Tonight I filliped the perches on the axle and changed the centers. That was after I did a mock up of the old spring assemble and the new one. Since I am going from a slipper spring to a spring and shackle, that changes the ride height. Also the new axle has more drop.....long story short after all the math, the new axle hub center is actually 1-3/4" lower than the old one relative to the frame. So that means it will ride about that much higher. I want to keep the fenders about where they are, they make nice steps to access the boat at that height. The new tires are about 1-1/2" taller. but taking the new axle hub center into account, clearance isn't an issue. This took some brain damage, and assuming I did the math right it will work great!
Here is a shot of the old axle and the new one. I had to cut the perches off, flip them 180, change the centers to match the trailer and weld them back on. I had to think about that since we are dealing with a round axle.
I started by leveling my build table. It has adjustable jacks at all 4 corners and i can get it within a 1/16 or so. I then cut one perch off, flipped the axle over and clamped it down flat to the table
After that I put the other perch on, adjusted the center and leveled it. I put 4 tack welds on it for now, then cut off the other perch.
Since the hub offset was now down, I just clamped the axle in the vice. That allowed me to level it and keep it from rolling around. Then I just repeated the process and welded on the second perch.
Here is a shot of the two next to each other after the welding
Assuming I have power in the morning, I'm going to get started on welding the spring shackles and mocking up the axle.