I have a 79 trans am w/400 pontiac in it. It came originally w/403, so it still has factory exhaust. I took off the turbo mufflers that I have run on it scince 1995, I was looking for more growl and a more powerful sound. So I bought 2 flowmaster delta 40's, and 250 bucks or so later, now I would swear its quieter than before. No growl to it at all. I dont know much about the motor, other than its got a 490 lift lunati cam, so it has a lope at idle. I was hoping it would be at least as loud as the 305 comaro that is in my neiborhood, but not even close. I almost think my v6 firebird is louder than my 79 now. My question is, could it have anything to do with my catalytic converter, it looks to be factory, or do I need headers to get a powerful sound out of this car? any input would be great, thanks