I've got no cats on my Grand Marquis, but Ford's put a resonator in place of the rear cats:
I asked a good exhaust shop to replace the resonators with a straight pipe, but the exhaust rattles like mad under load (anything past half throttle), because they used an el cheapo tin pipe.
Apart from the rattle, other changes were positive and I'd basically like to replace what the shop welded in with a quality straight pipe or a better flowing resonator. Just wondering if anyone has any recommendations.
The measurements, if of any interest, are:
Manifold to resonator
Circumference: 7.1"
Diameter: 2.26"
Length (top): 14.1"
Length (bottom): 16.2"
Resonator
Circumference: 11.2"
Diameter: 3.57"
Inlet: 2.26"
Outlet: 1.9"
Length: 10.6"
Resonator to H-Pipe
Circumference: 6.1"
Diameter: 1.9"
Length: 10.1"
I'm looking at an exhaust upgrade next year, when I will be going with Stainless Works long tube headers, offroad pipes and cat back. I don't want to revert to stock and put these the resonators back on, as the engine feels effortless on the highway, so I just want to get rid of the rattling for the time being. Thanks!

I asked a good exhaust shop to replace the resonators with a straight pipe, but the exhaust rattles like mad under load (anything past half throttle), because they used an el cheapo tin pipe.
Apart from the rattle, other changes were positive and I'd basically like to replace what the shop welded in with a quality straight pipe or a better flowing resonator. Just wondering if anyone has any recommendations.
The measurements, if of any interest, are:
Manifold to resonator
Circumference: 7.1"
Diameter: 2.26"
Length (top): 14.1"
Length (bottom): 16.2"
Resonator
Circumference: 11.2"
Diameter: 3.57"
Inlet: 2.26"
Outlet: 1.9"
Length: 10.6"
Resonator to H-Pipe
Circumference: 6.1"
Diameter: 1.9"
Length: 10.1"
I'm looking at an exhaust upgrade next year, when I will be going with Stainless Works long tube headers, offroad pipes and cat back. I don't want to revert to stock and put these the resonators back on, as the engine feels effortless on the highway, so I just want to get rid of the rattling for the time being. Thanks!