Lanny, I'm with K-roc on this. I thought you looked at my nuts last summer and decided that they really were SAE
Trevor, I have Berg's monster manifolds (TB style though) and the 3/8\" x 8mm flanged nuts are the Shatz. I use a 3/8\" x 1/4\" drive swivel socket on a 10 or 12\" 1/4\" drive extension and it works really well, the best I could figure out.
The nuts that Bruce mentioned won't work with my manifolds or any of the truly big uns, but they are OK for exhaust. There is a tall 11mm (3/8\") x 8mm nut in steel or Brass that I prefer for exhaust.
speaking about exhaust, Lanny, don't you suffer from bad exhaust?
Happy Holidaze!