blau928

Some of us have full dual 3 inch tubes from the headers all the way to the tailpipes.. There is room for an X just after the headers at the junction where the old cats used to sit.. There is enough space after this to put 2 Random High Flow Cats and the like after the merge collector...

HTH,

danglerb

Flowmaster and HP loss go hand in hand.

fraggle

Thanks everyone. Stock, aye? hmmm that means an X-pipe & cats stays on the to-buy mod list.

blast, there's no saving cash anywhere! I like the sound of my '87 "larger" pre-mufflers + RMB. Loud enough to be nice, but not obtrusive or irritating on the freeway.

Mongo

But danger.... I like the 'every single bit of plastic rattling' rumble of the Flowmaster

Mongo

Found the recipe....gonna try an X-pipe collecting into 3.5" and running it to a flowmaster Delta Force 40 series at the back of the car. Should sound just a little loud.... I will return with news

danglerb

Too many Mustangs running flowmasters, I just get tired of the sound. Magnflow and Borla are more to my taste, and Magnaflow makes so many models getting the right size, flow, muffling, that you want isn't too hard.

Before I get into the cat back, I want to sort the cat forward since that effects the basic sound, especially the Y for a 16v.

Warren928

I think you should leave it alone or do a RMD for more noise if thats your goal. The stock exhaust is engineered really well and is of A1 quality.
Unless you have a supercharger warranting a huge exhaust, dont mess with it or you'll look as rediculous as this guy:

danglerb

Wow, hate to be around that in the morning when the cats sleeping in it come flying out.

Two certain changes for my 83, (I'm just hyjacking, not the OP), are 85/86 manifolds which require a longer pipe on one side of the Y, and a modern high flow cat when the Y gets replaced. The new cat back is to increase the flow, and tune the resulting sound to my personal tastes.

Bill51sdr

My sentiments exactly Please Andy, don't go the fart can route. Your girlfriend already hates your 944, don't make her hate the 928 as well.

Mongo

Relax guys it's not going to be a 5" coffee can sticking out of the back of my car. The thing will have a resonator integrated into the system too before going into the muffler. I am sick of getting a little hot under the passenger rear while adding ATF. I'm still going to keep the exhaust system that I have on it now for later on...