My question is how much will be gained by putting a full catback system on as opposed to just putting on a new Flowmaster muffler? I am assuming that the most restricting part of the system is the muffler and I am wondering if just replacing that and keeping the stock piping will be OK. I have 1996 F-150 300/6 and I would like some added sound along with some added getup. Please let me know what you guys think. Thanks.

 

If your after sound, just replace the muffler with a pipe. Getting a cat-back is not going to make that big of a difference. My brother has a 94 150 with the 302, and has tried numerous different systems. None of them are going to give you a seat of the pants change. Unless you put on a different system from the head back, it is not worth the money to drop in a cat-back.
Just my .02

 

A muffler exchange is a good idea for that combination. You'll get a nice HP boost, your sound of choice, and a thicker wallet.