'68 318 to carbed Magnum 5.2: Check my checklist

I used the same flanges on my dart with hemi manifolds, and I'm using the flat flanges. After about 500 miles, one started to leak. I loosened it and retightened it, went away for a while, but it's still barely leaking. I'm probably going to rebuild my exhaust soon anyway, so I'm too concerned, but you are probably thinking right on the flanges.