I have a 94 3.9 Mag, and i heard that the stock exhaust manifolds on a pre-mag are bigger than the stock manifolds on a magnum. Since i cracked my passenger side manifold and it needs replaced, can i get two pre mag manifolds and bolt them on with no issue's? Will it fit onto my stock 2.5 inch pipe? Is the EGR channel on the same place on the pre mag manifold? How much performance would i see from doing this?

Also a kind of random question out of topic, would anybody have a guide on how to clean the EGR system on my Magnum?

Any answer's would be greatly appreciated, want to make sure i get all required part's(if any, besides gaskets and bolts) before i pull the manifold's off.

 

Never heard of that. But you might be thinking of 92-93 Magnum manifolds are better than the later ones. But headers are still better than stock manifolds no matter what year.