My car had single exhaust as standard. I ended up fitting a larger pipe and made the routing much straighter. I still have the single pipe system, but as soon as I get some spare cash, I am going with twin pipes.

6sally6 wrote:

How MUCH larger Stevo? 3"?  Might be big enough to get the job done without going to the added $$$ of dualling it out!
With a free flow muff (or NONE!)
6sal6

It's just a 2.5" pipe Sal, with Walker muffler... But it's pretty straight. I still reckon twin 2.5" is the way to go.



free pic hosting

There's nothing inherently wrong with a single pipe.  Due to the constraints of the floorpan and how low the cars were all 3rd and 4th gen F cars had single exhaust feeding into a transverse muffler.  The pipe was 3" diameter in the performance applications, including a 3" in/3" out cat.  A lot of people poo pooed this, but a 3" pipe actually has more volume than two 2.25" pipes, and if you went to an aftermarket system with 3.5" pipe, that has the same volume as two 2.5" pipes.  From a performance standpoint volume is volume and flow is flow.  What I will say is that those cars never sounded great IMO.  The 5.0s always sounded like a performance car, whereas the F cars sounded like a truck with a freer flowing muffler.  I've owned both, modded and driven both, but the Fox cars were just better cars in almost every way.  The F cars did handle better though, and the best rear suspension setups for the Fox essentially just copy the F car setup, which is why there's a MM panhard bar on my '89 GT now, and maybe a torque arm in its future.