If I want to keep pipe, but just replace the stock Muffler on my 04 Screw 5.4L, what size Magnaflow do I need?? Should still be a touch louder than stock, right?

 

Yes, it'll be louder.....Don't quote me on this, but I believe you're looking at 2.5" stock piping.

 

the stock muffler is 30" long (i believe?) and the largest magnaflow i think is 24", so either way you will need to add a little extra piping. the 24" will barelly be louder then stock, the 18" will be decently louder at full throttle but still pretty quiet, and their 14" straight through mufflers are their louder ones, giving a nice throaty sound at acceleration. all depends on how loud you want it.

and yes DieselWeb is right, the stock pipes are 2.5" diameter, so be sure the muffler you buy is a SISO (single inlet/single outlet) with 2.5" diameter both in and out.

 

Thanks.

I didn't feel like dropping big $$$ on a Gibson stainless CB unit So I thought the 24" Magnaflow muffler only option would be my next cheapest alternative that is still quiet enough it won't annoy me when pulling large trailer....

 

You will probably barely even be able to hear that....I wish my 14" maggie was louder...

 

I'm also in the market for a Magnaflow..., so a quick question:

Whats the difference between the round and oval shapes? Does it produce a different sound or anything?

 

get a flowmaster super44!! no low end power loss and its loud as h*ll.