Years ago when I built the 56 it came with a 12 bolt "Camaro" housing that some one had torched off the old hangers and installed spring pads....Under the paint was that exact porous pattern you have.....I filled it with brass to prevent any oil weeping....painted it and called it good....Until that day when leaving a friend's little get together I did the biggest burn out I believe I ever did...Later that evening I had gone in to the garage to wipe off the truck when I noticed an Amber fluid under the truck.....My worst fear came true, the housing had broke in two exposing the axle between the cracked right axle tube. I repaired it in the truck....knowing my repair was substandard....It had lasted 15 more years until recently, oil started dripping in another area of that weld...Long story short...I was able to buy a Moser replacement housing with 1/4" tubes and cast steel center.....Added my own spring perches and built it knowing it will never fail......This will be your weakest link in that 9", especially with the power your building into to it,,,
My suggestion would be to disassemble it and try to slip tubing in the inner wall of that area and plug weld it,,,,You could do it on the outside but it would be seen like a scarf patch....Just an opinion
