Can I get Opinions on Exhaust systems?

[Fordboy71]

I’m thinking about installing my own exhaust system on the ‘71 Mach 1. I’m going to stick with the factory 351c manifolds and just replace the dual exhaust system. Anybody had really good/bad luck with the kits? Thanks!

 

[will e]

I never purchased an entire kit but I did buy some end tubes, the ones that go over the rear axle and they didn't fit right. Be especially wary if your car has been modified. I have always found that going to an exhaust shop is the best option. They work around whatever is there.

 

[Sheriff41]

Most kits are designed for cars without the competition suspension option, that is, without staggered rear shocks. If you Mach 1 has the competition suspension, then you're options are limited.

Precision Exhaust (https://www.precisionexhaust.com/) is regarded as making some of the better replacement systems and does make kits for competition suspension-equipped Mustangs.

NPD also has a good selection of kits.

 

[Spike Morelli]

I bought my entire exhaust system, headpipes back, from NPD, factory system. The only change was to run a pair of Dyno-Max mufflers. I had a muffler shop do the install.. They said it all fit perfect.

 

[351c1971]

I used the NPD factory system with Hush Thrush turbo mufflers. I had to twist the left tailpipe to clear the left non-staggered shock and factory 1/2" sway bar. Otherwise the install went well.

 

[Stanglover]

I too stayed with manifolds which limits you to 2 1/4" pipes unless you use an adaptor for 2 1/2" or hog out the manifold openings. This is the area of restriction. Stock openings are 2' diameter. Boss manifolds are 2 1/4". Mustangtek list D1ZE-9431-BA, driver side for both 351 4V and Boss, but do not list passenger side ??. If that is correct, then the openings are just machined a 1/4" dia. larger for the Boss.
On my car, the H pipe (installed by the PO) was still good and solid, but I had a shop make up the tail pipes sections. However, they could have done a better job positioning the chrome tips. For mufflers, I chose Flowmaster Flow FX and really like them over the Flowmaster 40's that were on the car. Way too much drone with those.

 

[RIBS]

I used the NPD a factory style for my 302. Great system but the H pip I bought with it didn’t fit so well….very good otherwise.

 

[Stanglover]

I’m thinking about installing my own exhaust system on the ‘71 Mach 1. I’m going to stick with the factory 351c manifolds and just replace the dual exhaust system. Anybody had really good/bad luck with the kits? Thanks!

Is your car an H or M code? You do not give a description.

 

[351c1971]

I used the NPD factory system with Hush Thrush turbo mufflers. I had to twist the left tailpipe to clear the left non-staggered shock and factory 1/2" sway bar. Otherwise the install went well.

Correction it was the right tailpipe I had to twist. I will be replacing the turndown tip on the right one piece tailpipe to to compensate.

 

[Spike Morelli]

I mentioned that a muffler shop installed my pipes. They may have run into some Ill-fitting part of the system, I don't know, they said it all fit well. I do know, that a muffler shop can spot an issue, and rectify it in seconds. They have your vehicle up on a lift, they have benders, spreaders, can throw a torch at a bent and move a pipe angle, the discussion of doing it yourself, as opposed to having a place that does even harder installs all day long, is lost on me. Since my first car ( a Model A ), I was fortunate to have a major muffler shop close to my house. Their name was Huth Muffler, and the father designed a hydraulic tubing bender that was widely used by a lot of shops. Four or five lifts going all day long with customer's cars. Mrgmhale, here on the boards, grew up in the same Valley I did. He might remember Huth Muffler as well, on Ventura and Lindley. They even hand built the over-the-frame headers for my '34 Ford coupe hot rod with a Chrysler Hemi. Custom muffler shops are getting scarcer, but oh man, it's a rite of passage to any gearhead, to drive your car with headers "uncorked" to the muffler shop to get the mufflers and tailpipes installed!

 

[Q1SVT]

I too stayed with manifolds which limits you to 2 1/4" pipes unless you use an adaptor for 2 1/2" or hog out the manifold openings. This is the area of restriction. Stock openings are 2' diameter. Boss manifolds are 2 1/4". Mustangtek list D1ZE-9431-BA, driver side for both 351 4V and Boss, but do not list passenger side ??. If that is correct, then the openings are just machined a 1/4" dia. larger for the Boss.

Yes, the factory just had them machined out to 2 1/4... something a machine shop can do very easily. and worth doing if running exhaust with modifications

Fordboy71, you didn't mentioned what body style you have... some kits do not work with Convertibles, because of the added stiffing like cross member plate.

I like the Magnaflow for a 1970 stang [yes a 71-73 are a touch longer bodies, and a couple of inches wider... both are very easy to adjust for. but not for a convertible! ]
https://www.magnaflow.com/collections/1970-ford-mustang-exhaust-systems

 

[Fordboy71]

Thanks for the input everyone. And thanks for the trip down memory lane Spike Morelli. Loved it!
This is a Sportsroof Mach 1 with a 351C and automatic.
Believe it or not, shops are getting pretty stuck up here in TN. Several shops I called said they won’t touch anything as old as a ‘71 (same story I got from transmission shops)
The one exhaust shop that did say they would do it, is 47 miles away. So I thought, if the kits were good, I’d just do it myself on a lift. It sounds like I may be renting a trailer and taking a 47 mile ride though!

 

[Steve McMahan]

If you have a lift, I’d say, go for it. Some of us did our systems on our backs and they work fine. Mine is hand built from the shorties to the mufflers. If you get it installed but not completely satisfied with the outcome, you can always drive the 47 miles for an exhaust system install tune-up!

 

[rcadd1ct]

Thanks for the input everyone. And thanks for the trip down memory lane Spike Morelli. Loved it!
This is a Sportsroof Mach 1 with a 351C and automatic.
Believe it or not, shops are getting pretty stuck up here in TN. Several shops I called said they won’t touch anything as old as a ‘71 (same story I got from transmission shops)
The one exhaust shop that did say they would do it, is 47 miles away. So I thought, if the kits were good, I’d just do it myself on a lift. It sounds like I may be renting a trailer and taking a 47 mile ride though!

Asking as you have some tube off the manifolds supported by a coat hanger you could drive 50 miles

Hell I drove a week with glass packs clamped directly to headers held up be a coat hanger back in the day.

 

[Hemikiller]

NPD and others offer 2 1/4" intermediate pipe and back systems as well as individual components, that follow the stock routing. They also offer H-pipes for 302, 351-2V and 351-4V with stock manifolds. The tailpipes are designed to clear the staggered shock on the driver's side, if you're equipped with it. If you have a specific muffler you'd rather use, ie: Walker Dynomax Super Turbo, get the individual parts.

Kits
https://www.npdlink.com/1965-1973-m...yle-dual-exhaust/1971-1973-351c-429?year=1973

Individual parts
https://www.npdlink.com/search/prod...ST+PIPE%2C+Outlet&top_parent=200001&year=1973
https://www.npdlink.com/search/prod...E%2C+INTERMEDIATE&top_parent=200001&year=1973

H-pipes
https://www.npdlink.com/search/products?search_terms=h+pipe&top_parent=200001&year=1973

 

[mjlan]

Hell I drove a week with glass packs clamped directly to headers held up be a coat hanger back in the day.

You actually supported them?

Overacheiver.

Mine dangled free for at least a year. At that point there was no packing material left. Ah glasspacks...

 

[Fordboy71]

You actually supported them?

Overacheiver.

Mine dangled free for at least a year. At that point there was no packing material left. Ah glasspacks...

Boy, did you just take me back, at least 35 years. In 88 I bought a solid 74 mustang II for $50. A glass pack was $12.99 and gas was .78 a gallon.

 

[will e]

Boy, did you just take me back, at least 35 years. In 88 I bought a solid 74 mustang II for $50. A glass pack was $12.99 and gas was .78 a gallon.

Remember you'd walk into the local parts store and they'd have a basket of 'Cherry Bomb' mufflers. The good old days.

I sport a pair of glasspacks. I just like the sound.

 

[Bobby]

Wrangling with a non-stock exhaust system is always tricky. I would tell you to get some nice headers of your choice and go to a custom muffler shop and have them order your mufflers and tips (if you so desire) and let them do the whole install. The money will be well spent and it will look like a professional job. Going with headers from the get go will save you time and money and the "I wish I had headers installed to begin with." Better sound and performance!