I used them on a 1970 GMC C25 with a 406 SBC for about a month and a half before I got bored. And I like noisy cars. They take the high-pitched screech of candid headlines and turn it into a deep, head-splitting roar. With 4.56 gears on the Autobahn, it was simply deafening. I didn't want to drive it. If you're looking for loud ones, this is a little more subtle than open titles. That's it.