So yesterday I pulled my header off and gutted the cat, now I am having an issue getting the cross over pipe underneath to stay tight and connected to the header pipe. Everything lined back up good and had no issues bolting back up to the engine.... Anyone experienced this? If so what was the fix?

 

I just did mine a week ago and didn't have that problem. Sounds like you're not getting the cross over pipe back in far enough. Try again... loosen it all up, push it tightly in place and tighten it up slowly, making sure the looseness is gone.

 

Not sure if this is your issue but those torca clamps (or whatever they're called ) are supposed to be a one use clamp.