Bowhay,
A Hooker Muffler is the same as a glasspack in the fact that it has insulation inside. The insulation gets hot, burns together with carbon deposits, sounds bad after not too long. I have used them, do not like them, & for similar money you can get a much better muffler such as a Flowmaster for your truck that will sound great & not break the bank. There are others that are good too making any motor sound much better than a glass filled muffler system. Good luck!! Scooter