Guys, just getting the other half's L322 back on the road and fixed a few problems as well as fitting a 2010 interior but when it fires up it is almost like it has a very bad exhaust blow, as the car warms up and comes off cold start it is virtually silent, maybe a very slight tick from passenger manifold to downpipe joint. I cant believe a few 100 rpm can make so much difference, is there anything it can be emissions wise? IE secondary air pump system that not sealing?
It is LPG but I dont see that being anything to do with this noise. One day your life will flash before your eyes......................................make sure yours is worth watching!

My 04 had a split or hairline crack around the drivers side cat that sounded loud for a few minutes but then subsided as the revs dropped. The heat was possibly helping to seal it. Just welded mine up at the weekend

Same when we had a 4.4 V8 we had a crack around the cat also. Had to take the entire exhaust off and weld up. When you take it off you will see the joint is a weld and it will have gone there probably. Those exhausts get so hot so over time probably gets weak then cracks

Thanks guys I think its manifold to downpipe, mine has the cracked cat as well so will need to do that when hers is done. One day your life will flash before your eyes......................................make sure yours is worth watching!

There is no gasket between the manifold and down pipe just two nuts and a clamp over two studs fixed into the manifold.