The one time that I surface ground the clamps to reduce the depth of the seat and crush the dounuts more they didn't leak. The actual up-pipes just wrinkled up and push the manifolds off of the heads and sheared the rearmost bolt on the driver's side.
After that I was done with the bs pipes with ZERO provision for the hanus expansion/contraction that is unavoidable when you go from 2 or 300 degrees to over 1600 degrees in a few seconds, then right back to 400 or so, only to shoot right back up to 1700.
I now run these.
I'm sure that is what the H-max kit will also turn out like.
Work like a charm. I warped the driver's side flange that holds the bolts to the manifold, but I beleive that I might have overtorqued it a little in conjunction with the 1800 degrees egt and it's got a little curve in it now. I'll cut it off and straighten it out, but they don't F'ing LEAK.
Try 1800 degrees with 40pounds of boost on a 38R with the stock trash. These have been running for around 7 months now I believe. Tough as nails. (Tougher than the manifolds that warped, started falling off of the head on one side and cracked between 3 and 5 on the other)
I've got to give credit where credit is due. Other than the warped flange, they are flawless. Nice job David. (He mutters with great reluctance)