Exhaust Upgrade questions

I’d like to upgrade my standard 302 2V single exhaust to dual exhaust. No engine mods beyond electronic ignition. The car has original manifold. I’ve gotten two quotes but need some advice. My goal is make it sound similar to today’s Mustang GTs. I want it growl low but not be obtrusively loud. I definitely want to hear it on acceleration but don’t want it too obtrusive on the freeway. A little better performance would be a nice adder. Here are the questions:

  1. What size pipes? One quote was 2" and another 2.25".
  2. What type of muffler. One quote was Magnaflow the other Turbo.
  3. Straight tail pipes or turned down.

I realize this is very subjective but I’d like to hear what others have chosen or would choose.


I’m running a 302/4v with JBA headers, JBA H pipe, and no-name “turbo” style mufflers. 2.25" tubes, and the “GT-E” style twin-tips. It sounds pretty close to what you are describing, but still gets a little drone at certain highway RPM’s. A 5th gear would alleviate that for me.

Go with at least 2.25" tubes, unless you are certain that you won’t be doing a 4-bbl and/or cam swap sometime down the road.
Turn down pipes unless the valance is modified for “G” type exhaust tips or something similar.
Muffler choice is a matter of personal preference. (I like the combination of price/performance/sound of Walker Dynomax mufflers.) Go to a car show or cruise night, find a few cars with SBF engines that sound good to you, and ask what they’re running. There are lots of exhaust sound clips on youtube, which can help some, but in-person is better.
Be sure to have an H-pipe or X-pipe installed. The X-style is slightly more efficient, but the H-pipe will give more of a traditional muscle-car tone. Either one will improve the sound and efficiency over two individual pipes.

I like the sound of Flowmasters. I had a pair on a SBF 302 had they had a mellow sound at idle. Under throttle they sounded really good.

2" pipe with an x pipe and flowmaster 60’s.

Putting a 4v on it doesn’t do anything about the crappy factory heads and the manifolds. So, there’s no need for greater diameter pipe.

A stock 302 with duals does not need anything bigger than 2" pipes. Back in the day, stock 351W-4Vs with duals had 2" pipes. Performance-oriented 351C-4Vs used 2-1/4". Heck, even stock 390/428 and 429/460s with duals only used 2-1/4".

‘Sound’ is a funny thing. You do realize that new Mustnag GTs have shorty headers, right? And only 281 cubic inches. And 2" pipes, back to the rear-mounted mufflers with 2-1/4" exits.

Factory 351W dual exhaust had 2&1/4 inch pipes.
In the 1980s, Ford engineers determined that 2&1/4 inch dual exhaust provided the best combination of efficiency and performance on 302-equipped Mustangs, even taking into account the up-stream restrictions imposed by catalytic converters and relatively low-performance heads.
Hot-rodders quickly realized that with even modest modifications to the engine, the 2&1/4" exhaust system was restrictive, and aftermarket 2&1/2 inch and larger systems were extremely popular upgrades as a result.

We offer a factory copied H pipe, as well as complete systems with two chamber mufflers. Which will be louder than you are probably looking for.


Definitely use an “H” pipe, like was installed by the factory. “X” pipes are a little better, but to make them work optimally, they have to be placed in the ‘sweet spot’ between the collectors and mufflers.

My original exhaust system on my 428CJ car was 2 or 2-1/8 inches outside diameter at most.

What name brand are the mufflers? What length is the muffler body? Can the kit come without mufflers? Noticed the tail pipes are welded to the mufflers. Any videos of these mufflers installed?

Great kit btw for the diy and looks pretty easy to install with stock hangers and hardware. Maybe a future WCCC video…


I second the Walker Dynomax. It’s pretty much the same that I put on my '69. Mine are Walker quietflow SS and they are just loud enough with no real drone. They sound great when you put your foot in her.
I originally put Borla mufflers on and they were pretty loud even though the reviews on them said they were only about 80db at idle…horse pucky! They also had a bad drone at 2k rpm.
I have a 351W, 4 barrel Holley, moderate roller cam, roller rockers, and TL 4 spd with 2 1/2" exaust with rear turndown tips at the rear valence like original. Oh, and an H pipe crossover.
Runs like a scalded dog but needs 3.0 gears and detroit true trac instead of the 2.73 open rear it has now.