I forgot to add or take pictures (will tomorrow) of the inside. Since it was butt welded, there was a seam that needed to be sealed up. so, I ran a bead all the way around the inside seam and then ground it down.

This was my second flange/pipe combo. My first setup, the flange was slightly larger (mild steel as well) and I was able to fit the tubing inside the flange. I then welded it up just like you see in the headers ... full seam weld around the inside of the flange and full external weld as well. Inside was then ground down.

I wanted to do that with this flange, but couldn't because the opening was just too small. If I wanted to, I would have to slit one side and notch it and then crush the pipe down and close the notch and then seam weld that notch ... too much hassle. I'm very confident that this butt weld will hold just fine.

For Sale: 1997 Explorer XLT V8 AWD