318 1 piece pan gasket?

The only time i ever saw a one piece gasket was on a Magnum engine. What year is yours? I have a magnum 1 piece gasket I was gonna try using on my 360 but it doesn't mate up to the pan good. I'm sure it'd leak. Double and triple check things real good as it may not be the pan leaking. Several times I've seen it run down from a valve cover, leak from the oil filter adapter, even one that had a leaking sending unit and every time it ran down on the pan making it look like the pan was leaking.

Also did you check the pan over to make sure it was straight before you sealed it up? It isn't one of them cheap junk chrome E-bay pan's is it? They rarely seal right.