Pic #1, Break out the Lincoln 140C
Pic #2, There is a perfect spot on the block right below the head to put the welder ground on. I used a small angle grinder to take off the rust. Remember to unhook the negative terminal on your battery before starting to weld.
Pic #3, Thick washer that was a tad smaller than the hole, and a nut. I penetrated the washer perfect on the first try. However, I used 3 different nuts because due to the angle you have to weld at, it was hard to get penetration on the inside the nut. So I finally used a bit bigger nut and gave a good hot tack on the outside of the nut to the washer. Also the first 2 nuts, I didn't have the heat up enough. The bigger nut, I turned he heat up all the way, and had the wire speed on 5. In hindsight... the wire speed could have went to 6.
Pic #4, Washer held on with duct tape. No rom to hold it with a gloved hand. Be quick to blow out any burning tape. It WILL catch fire... trust me. But it's not a huge fire. Just be aware that you have to blow out the fire. I had a compressed air hose at hand with a nozzle.
Pic #5, First attempt at welding the nut. Held nut with tape too. This nut spun off when I put a socket on it.