exhaust question

Ok, I have an 86 5.0 with, cats, an off road h-pipe, and echo tips (don't know if that makes a difference in your sound). I want to put some flowmasters on so it will boost my HP, but I love how it sounds already and don't want to mess that up any. I've been doing some research and the new flowmaster super 40s sound like they're loud and make HP. I'm wondering if anybody has input on this, or knows of a good muffler that delievers HP and a very nice, loud, mean sound.

as i said in my other thread, i like dynomax. they outflow flowmaster 40s and in my opinion sound better. a lot of the guys on here like MAC as well

Ok, I have an 86 5.0 with, cats, an off road h-pipe.

It's like Sesame Street kids....

Which one of these things doesn't belong here?

I'm also wondering, what about Hooker? I haven't really heard much about them from anybody, but from what little I do hear they're good. Does anybody here have or know somebody with Hooker exhaust?
As for MAC and dynomax, I hear good things about them also.
Anybody here know a good site or magazine article that compares these mufflers? It would really help me out. Thanks

It's like Sesame Street kids....

Which one of these things doesn't belong here?

agreed... i'd say what it is but i'd like to see this guy figure it out on his own =P

dont they make off-road h-pipes with high flow cats.

It's like Sesame Street kids....

Which one of these things doesn't belong here?

I saw you had my choices at 86 5.0, h pipe, and cats. Lets break this down shall we?

1. 5.0 belongs b/c...well its the car
2. h-pipe, is a starting mod for your car so why would I throw this out
3. ah the cats, I could throw them, but I would have straight pipes and no back pressure for my car, so I need them at the moment

This brings me back to my question, what mufflers do you guys suggest for me? If I can get a good set and still keep the sound that'd be great. Or, if you could tell me if there's a number or something on the cats to tell me if they're made for backpressure it'd save me time and money. Thanks

Maybe I missed it. What kind of mufflers you running now?

Maybe I missed it. What kind of mufflers you running now?

None at all.

a 5.0 without flowmasters is what you have now. get 40 series flows. that have complete bolt on systems. thats your best bet. check out jegs and summitracing

my buddy and I put a Flowmaster American Thunder kit on his '88 GT and its loud when you want it to be and definitely sounds powerful but his H-pipe doesn't have cats (still starts fine when its 0 degrees outside-back pressure is overrated) any muffler short of a 3" glasspack will give you more back pressure than a high flow cat, I would take the cats off and put some flows on. :iceslolan

I saw you had my choices at 86 5.0, h pipe, and cats. Lets break this down shall we?

1. 5.0 belongs b/c...well its the car
2. h-pipe, is a starting mod for your car so why would I throw this out
3. ah the cats, I could throw them, but I would have straight pipes and no back pressure for my car, so I need them at the moment

This brings me back to my question, what mufflers do you guys suggest for me? If I can get a good set and still keep the sound that'd be great. Or, if you could tell me if there's a number or something on the cats to tell me if they're made for backpressure it'd save me time and money. Thanks

Maybe you should look at the post above this one....

off-road h/x-pipes do not have cats!

Maybe you should look at the post above this one....

off-road h/x-pipes do not have cats!

Ok GTStang I'll fill you in on this. I got the car 2 weeks ago and did some research and found that the 86 came with a h-pipe. Ok, the person I got it from took it to an exhaust place and wanted straight pipe on the thing. The guy working their told him that was a bad idea b/c he'd have no back pressure. So, he removed the mufflers but put on some cats for some back pressure.

your buddy's been had, stock h-pipes already have cats on them, which provide plenty of backpressure. i gotta put restrictors in my exhaust with no cats and super turbos to save my exhaust valves =)

Ok GTStang I'll fill you in on this. I got the car 2 weeks ago and did some research and found that the 86 came with a h-pipe. Ok, the person I got it from took it to an exhaust place and wanted straight pipe on the thing. The guy working their told him that was a bad idea b/c he'd have no back pressure. So, he removed the mufflers but put on some cats for some back pressure.


You do realize this makes no sense?

Ok GTStang I'll fill you in on this. I got the car 2 weeks ago and did some research and found that the 86 came with a h-pipe. Ok, the person I got it from took it to an exhaust place and wanted straight pipe on the thing. The guy working their told him that was a bad idea b/c he'd have no back pressure. So, he removed the mufflers but put on some cats for some back pressure. Are you even clear about cars at all? Off-road H-pipes have NO cats on them what so ever. Hense why they are called off-road and are not street legal.

I think everyone understands that V8 Mustangs 86+ all have h-pipes, weather thay have cats or not.

Now are you saying you have an off-road h-pipe, and some exhaust shop put cats on in the place of mufflers after the h-pipe?

well my friend has a 95 5.0, no mufflers just straight out pipes with hi flow cats. in NJ its a law to have cats or our cars will get impounded which is a b**** cuz i heard a 96 cobra like mine with an off road H pipe, it was hot to say the least. He is now getting Super 40s on his car, he tore off the exhaust when he hit a deer :frown: I prefer Flowmaster over Mac, nobody has the idle sound like Flowmaster does.

There is off road H -pipes with cats and without.
There is Off road X -pipes with cats and without.

They are considered off road because they don't have Federal EO or CARB numbers on them.


Any aftermarket part that you buy that alters the OEM design of the emissions system and does not have Federal EPA EO or Carb numbers is considered a RACE item AKA Off Road item.


If you live in California, you'll need CARB approval on basically anything engine related. This includes things like superchargers, cold air intake kits, fuel injectors, catalytic converters and even upper and lower intake plenums. If you have CARB or EO approved parts on your car and you modify them, they are no longer CARB or EO approved.

For example, you buy a Vortech blower kit for your mustang which has been certified by CARB and given a CARB number. It comes with a boost controler. You decide you don't like the boost controler, and you swap it out for another brand. The kit is nolonger CARB legal because you altered the way it performs, and Vortech did not certify the kit with that other component.

As far as cats, the EPA EO or the CARB numbers are required, and they must be certified for the perticular application. Technically, the majority of the H-pipes and X-pipes are not CARB or EO legal. Also, your not suspossed to swap out any emissions exhaust componet for the first 50k miles of a vehicals life, and if any emissions component fails, the dealer is supposed to swap the parts out. Once you hit 50k miles, then you the end user are allow to swap out the cats as long as it has EPA EO or CARB numbers on them.

There is off road H -pipes with cats and without.
There is Off road X -pipes with cats and without.

They are considered off road because they don't have Federal EO or CARB numbers on them.


Any aftermarket part that you buy that alters the OEM design of the emissions system and does not have Federal EPA EO or Carb numbers is considered a RACE item AKA Off Road item.


If you live in California, you'll need CARB approval on basically anything engine related. This includes things like superchargers, cold air intake kits, fuel injectors, catalytic converters and even upper and lower intake plenums. If you have CARB or EO approved parts on your car and you modify them, they are no longer CARB or EO approved.

For example, you buy a Vortech blower kit for your mustang which has been certified by CARB and given a CARB number. It comes with a boost controler. You decide you don't like the boost controler, and you swap it out for another brand. The kit is nolonger CARB legal because you altered the way it performs, and Vortech did not certify the kit with that other component.

As far as cats, the EPA EO or the CARB numbers are required, and they must be certified for the perticular application. Technically, the majority of the H-pipes and X-pipes are not CARB or EO legal. Also, your not suspossed to swap out any emissions exhaust componet for the first 50k miles of a vehicals life, and if any emissions component fails, the dealer is supposed to swap the parts out. Once you hit 50k miles, then you the end user are allow to swap out the cats as long as it has EPA EO or CARB numbers on them.


Blah Blah Blah

Tell you what write to 5.0 magazine and ask them if your h-pipe with cats is an off-road h-pipe and I guarantee you are Virgin of the month!

Go on corral or nay other big forum and and ask what off-road /x-pipe means.

Ok, everybody is saying this and saying that. The guy I got the car from said the car had an off road h-pipe on it. He wanted straight pipes on the thing so he took it to an exhaust shop. The guy at the place he was getting this done at said "that's a bad idea, you'll have no back pressure with straight pipes." The guy I got the car from didn't want mufflers or anything, he wanted straight pipes. The guy at the shop finally convinced him to put some cats on it to give the car some back pressure.

You can believe me or not about this but that is what the guy told me. If you guys really want to know, no, I don't know jack about cats, off road h-pipes, or exhaust systems in general. I know the very, very basics and thats it.

Ok, everybody is saying this and saying that. The guy I got the car from said the car had an off road h-pipe on it. He wanted straight pipes on the thing so he took it to an exhaust shop. The guy at the place he was getting this done at said "that's a bad idea, you'll have no back pressure with straight pipes." The guy I got the car from didn't want mufflers or anything, he wanted straight pipes. The guy at the shop finally convinced him to put some cats on it to give the car some back pressure.

You can believe me or not about this but that is what the guy told me. If you guys really want to know, no, I don't know jack about cats, off road h-pipes, or exhaust systems in general. I know the very, very basics and thats it.
Tell you what, just take some pics of the underside of your car and well see ecaxtly what yur talking about.

Ok, everybody is saying this and saying that. The guy I got the car from said the car had an off road h-pipe on it. He wanted straight pipes on the thing so he took it to an exhaust shop. The guy at the place he was getting this done at said "that's a bad idea, you'll have no back pressure with straight pipes." The guy I got the car from didn't want mufflers or anything, he wanted straight pipes. The guy at the shop finally convinced him to put some cats on it to give the car some back pressure.

You can believe me or not about this but that is what the guy told me. If you guys really want to know, no, I don't know jack about cats, off road h-pipes, or exhaust systems in general. I know the very, very basics and thats it.


Maybe through whatever circumstances someone took and off-road h-pipe an then had cats welded on to it after. But what I'm and others are trying to explian is that an off-road x/h-pipe means the h/x-pipe has no cats on it. That is how it is in this lil Mustang driving world.

If someone welded on cats after the fact it's not really an off-road h/x-pipe anymore.