I have been useing the Mrgasket (155) for well Over 17yrs. Offey intake & headers, Clifford intake & headers, My Intake(3x4) Headers Then even with my own Headers. And Never had a issue.If i know I maybe taking things back apart and back together Soon I'll use the Copper RTV.
Everything is always PORT Matched to this gasket. I tighten things down from the center and work my way OUT which is the way it should be done ,EVEN with a STOCK set-up. And with any after market set-up(headers or Intake) studs are better to be used. And eventhing is retorked after 2-3 heat cycles.I have also Nkown guys to Not even use a gasket But only the copper RTV. and Not had issue. Personaly I think you need to take a Close look at you head (intake/exhaust side) to be sure that it is TRUE/FLAT.
Also I have lockwashers On each stud.
God doesn't like ugly.
