My brother has some on his 68 XL and he stated that he would Rev his motor up at really high RPM and shut it off at the high RPM everytime he would get out. he stated that this will leave unburnt gas in there and will cause them to burn out faster to create the sound he likes. I don't know if this is all true because I did not do it but that is what i have heard. I do know it is LOUD. Give it a try unless someone else has an oppinion.
I hate to point it out but revving your motor up real high and turning the ignition off will definitely chuck unburnt fuel down the exhaust system which isn't good for your catalytic converter. As well, all that unburned fuel washes down the cylinder walls and removes the protective oil coating leading to accelerated wear/abrasion of the cylinder walls/piston skirts and also pollutes your oil.
It's also a way of exploding your muffler if too much fuel gets in there the next time you turn the key to start it.
Location: Houston, by way of every major city in America.
I've had my no name glasspacks on for almost two years now, and they still have not become that much louder. Wonder what I'm doing wrong, I need a louder more noticable exhaust Guess flowmasters are in my future, huh.,,,,98
I did mention it was aon a 68 right? back then they did not have cats. or any of that smog junk. Like I said it worked for him but hey who really knows. I do know that he tried the water trick and it did not work. It really depends on your year and mods that you have made to it. I know that I was able to cut my cats on my 92 Bronco because they were after the O2 sensor and no it did not mess up the back flow.