94 Sub with 350

any ideas on why engine sounds so loud in the cabin; like exhaust is not making it back to tail pipes; 94 350 all stock best I can tell with 190k; and if I might be so bold to ask a second question.... how do you change the bulb in license plate lights on these step up bumpers... wants to pop back in like it's spring loaded and can't get to from underneath.

What sort of sound is the engine making? Does it sound good or is it knocking or anything like that? When was the last time it had a tune up?

engine running fine just sounds loud inside front seat; exhaust used to growl so nice from pipes, now sounds like coming from under hood; could it be manifold gasket?

i'm no expert, but that would be a good thing to check. maybe just stick your ear down as close as you can to the manifolds and see if you hear a leak in the exhaust. or just see if you can pinpoint any sort of loud noises.

On further inspection, noise appears to be coming from fan shroud but fan is not rubbing anyplace; could it be a bad fan clutch? Any help on the step bumper license plate lights would be appreciated