cab noise from exhaust

2000 silverodo 4x4 dual exhaust 6.0
the noise inside the truck at 70+ is like being inside a drum.
The sound outside is great its after being on the road for eight hours that you cannot stand it. ? noise reduction inside.

get on ebay and buy sound deadening called e-dead. i did my entire truck in it and it makes it really quiet to road noise. i would double it up on the back cab wall and the floors. i did the floor, doors, above the headliner . i stripped the truck down and did it. it was bare. alot of work but well worth it. i bought 120 sqft and i had extra when i was done. hope this helps.