I am wondering a couple of things. I need to put an exhaust in my car asap. Do to money problems and shops i cant install a mandrel bend exhaust all the way to the tips. So i am going to do straight exhaust and dump it right before my rear end. Now the question is almost all exhaust shops only have flowmaster mufflers when they are doing exhaust. So is FLOWMASTER good or horrible?? If bad what are the best mufflers for performance and nice sound?

 

Spintech.

 

Spintech

 

Dynomax Ultra flow will work better than the Flowmaster. Just make sure your muffler, regardless of brand can flow more than 1000 cfm. 1000 cfm is the no restriction flow number for a motor that produces 454HP. Their catalogue shows one particular model that flows 1195 cfm. This is good for 543HP. Unfortunately, it's hard to get flow numbers from a lot of manufacturers, because their products suck. I was at a tradeshow yesterday and asked the Magnaflow rep about flow numbers for their catalytic convertor (which will be your primary restriction in the exhaust system more so than the muffler), and he said that most manufacturers don't publish cfm numbers for good reason. But their product does flow more than stock. (Anything over 300 cfm which is about close to the stock convertor and a restriction for anything over 136HP is considered high flow.)

I remember Walker published CFM numbers for their mufflers in their parts catalogue if you work in a parts store. They do not release those numbers to the general public on their website. If you can make it to an autozone or Pep boys and ask to see a walker catalogue, it may still show cfm ratings beside their mufflers. This was a few years ago for me, so I don't know if they still do it.