msmith

I recently bought a really nice 66 convertible with a C-code 289, low miles and in VERY original condition. About the only items not original are an aftermarket A/C and the dual exhaust.

This dual exhaust appears to have been recently installed and it is a POS. It sounds flatulent, burbles like a cheap percolator when you let off the gas, lacks resonators and has Pep Boys chrome tips on it. To make matters worse, the butchers who installed it drilled new holes for the hangers and mounted the tailpipes too close to the leaf springs. As an added bonus, the mufflers heat up the floor pans pretty noticeably to the point that the seat belt bolts will burn your ankle if you sit in the back seat.

SO.... here is the dilemma.

Since the car is so original otherwise, I've been seriously considering putting it back to original spec with a single exhaust. A few motorheads I know looked at me like I was some kind of pansy when I mentioned that, but the car is not a drag-strip car... it's a cruiser and this would solve some of the heat issues and ugly sound issues.

The other option is to put a good quality dual-exhaust system in it that is not too loud.

I'm leaning towards the single exhaust... talk me out of it.

2+2GT

The original exhaust was a single system with a large, low-restriction transverse muffler and a resonator below the right rear seat. This was used on the 289 2V AND the high-compression 289 4V engines.

For cruising and enjoying the day it's just the thing, it'll end both your noise and heat issues. So- Who are you trying to impress, your family, or the yokels at cruise night?

Carlos Pineiro

There's no real harm in the factory style single exhaust, but your car will perform and sound better with duals. Install what makes you happy, but don't be too concerned about originality. Concourse correct cars with matching numbers everything are trailer cars that just get taken to shows and back and never get driven. If your car has steel belted radials instead of polyglass bias tires and a maintenance free battery you don't have to add water to, you are already driving a modified car (like almost everyone else).

If dual exhaust (installed by the dealer on many original Mustangs as an option) is installed correctly, you won't have the heat issues. Get performance mufflers like Flowmasters that don't sound like wet farts and it will really enhance your car.

You can hear samples of exhausts on YouTube if you poke around there. Good luck.

CP

bodyputtyless

You should do whatever "YOU" want. Personally I would ask around at a weekend cruise in and ask the fellows who has the best exhaust shop. Then I would have a set of custom made aluminized dual exhaust with Flowmasters. Nothing wild mind you, but a nice deep slight rumble. Three chamber I believe. But thats me.

Starfury

If he wants an even, smooth, tolerable sound, I'd recommend against duals w/Flowmasters. Turbo mufflers or the OE-style single exhaust might be more in order.

msmith

Thanks for all the input, guys.

Carlos, you're right that the car is not concours condition and has modern tires, battery, etc... but I guess I am looking to keep it as original as is practical and safe. I do plan to put a dual-bowl master cylinder on it, for example. But since it is in unrestored condition (original paint, interior, etc) and is in nice shape I don't want to "screw it up". I love a nicely modified Mustang, but this one just seems too clean to mess with too much.

Here's a gallery of the car, including some under the car shots of the current exhaust I'm not happy with:
http://gallery.me.com/msmith954/100013

Bodyputtyless, of all the dual exhaust setups, is that FlowMaster setup the mildest in terms of "roar" at steady highway speeds? (I don't mind a little racket at WOT). Anyone else with a "mild" dual exhaust recommendation?

Appreciate you guys' time and expertise!

tx65coupe

Why not put OEM style dual exhaust on it? You can get that from most Mustang shops like Mustangs Unlimited etc. Have you looked at those yet?

I guess you need to be a member to look at the images.

Starfury

Like I said, I wouldn't recommend Flowmasters. I think even the 50 series would be too much for your taste. I ran Turbo mufflers for a while and I think they'll be exactly what you need. Mild at idle and while cruising, but they have a decent aggressive tone under WOT. The only thing I didn't like about them is that they have an odd raspiness above 3k rpm.

rst08tierney

FlowMaster 40's are perfect, especially for long drives and screaming at other people in the car.

Carlos Pineiro

Just as a reminder, it doesn't affect the credibility or originality of the vehicle to install duals. It's not like you were changing the paint color. The only effect will be a performance upgrade, and possibly a bit more gas mileage.

If you do decide to get dual pipes, even the pressure with a H or X pipe. Just make sure the muffler shop doesn't do a bad install like the last one. Exhaust is not supposed to betouching the floorpans or seat belt bolts. Good luck.

CP