I've got a few questions about swapping out mufflers. I picked up a, shall we call it, fixer-upper. '77 F150 Ranger. It has had some work done on it, including a new exhaust system...which I hate. It is very loud and rumbley, and I would like to have it factory quiet. The new mufflers they put on it are welded to the pipes. If I break out the sawzall, can I just cut them off and replace them with a couple of OEM type mufflers, or is there more to the job than that? Here's pics of the system, front, mufflers, back.

Thanks.

A good exhaust man makes this work look easy, but for the amateur (non-professional, not incompetent), it can be a huge pain in the butt. You do appear to have room to work, and the pipes look new-ish and not rusted. That helps a lot. The previous work also looks well done, not cobbled up.

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If I break out the sawzall, can I just cut them off and replace them with a couple of OEM type mufflers, or is there more to the job than that?

If you have welding equipment and expertise - preferably MIG - that would help a lot. Sometimes there are issues with the size of the muffler inlet & outlet ID vs. the pipe OD. They need to slip over the pipe, not butted together. You might need a pipe expander. Pipe expanders I advise against using adapters and /or clamped joints - the more you have the more likely they will have pinhole leaks.

I think those are what they call straight-through mufflers. I had something similar back in the late 80's on my 1967 Firebird, they were called glasspack mufflers. Very loud.

If you have the clearance I think you can put regular quieter ones on.

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Originally posted by egregore:
If you have welding equipment and expertise -

I have the welder, but am a tad shy on the expertise side.

I was thinking that cutting them close, making sure the ID and OD match up, and getting new ones of the right length, I could just slip them on there and clamp them down with the old style U-bolts and maybe get them welded at some point.

Will the length and shape of the back end pipes make any difference on sound, or is it all in the right muffler?

Yes the tail pipes can make a difference depending on where they end, if it's turn downs under the bed you'll have a louder exhaust, for quiet you want them straight out the back, should end right at the bumper, not past, or you can turn them out left and right behind the rear wheel.

Those look like Flowmaster Mufflers or clones, they are louder, deeper exhaust and popular with that era v8 engine machines.

Link

I would take it back to the shop and tell them it's way too loud and you don't like the mufflers and want quieter mufflers, looks like the work is good, just the part is wrong.. the pre and post muffler work looks good and they exit out back so just change mufflers.

I had Flowmasters on my Corvette, the sound outside was awesome, under throttle it was loud and aggressive, inside was like living in a can with someone pounding on it with a big hammer.. Replaced them after the fun wore off with quieter but better performing whole system.

When I worked on cars, I found exhaust work to be not worth the trouble (to me). I either sublet it, sent the client to a muffler shop, or, when I worked in a Midas franchise, let any of the three other men do it. (There was plenty of other work for me to do.)

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Originally posted by HRK:
Yes the tail pipes can make a difference depending on where they end, if it's turn downs under the bed you'll have a louder exhaust,

So with the existing pipes that go up then down under the bed, even if I put quiet mufflers on it may not give me what I'm after? Shoot...more money....

It's no different in my line of work.

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Originally posted by egregore:
When I worked on cars, I found exhaust work to be not worth the trouble (to me). I either sublet it, sent the client to a muffler shop, or, when I worked in a Midas franchise, let any of the three other men do it. (There was plenty of other work for me to do.)

Totally agree with this.

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So with the existing pipes that go up then down under the bed, even if I put quiet mufflers on it may not give me what I'm after? Shoot...more money.... Big Grin
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You may also consider adding a muffler in front of the existing ones. If you clamp them, there is a good chance that they might try and turn, welding would be best. Might have to add a hanger there also, that's a long run without extra support.
I have a 1976 F250 4x4, you have not yet come close to spending money on that truck, it will never end .

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Originally posted by Gustofer:

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Originally posted by HRK:
Yes the tail pipes can make a difference depending on where they end, if it's turn downs under the bed you'll have a louder exhaust,

So with the existing pipes that go up then down under the bed, even if I put quiet mufflers on it may not give me what I'm after? Shoot...more money....

Maybe, but think it's those Flowmasters that are your problem, they are straight through mufflers, meaning no curves and little if any sound deadening.

Flowmasters are a good muffler if you like performance and louder sound.

You want something that puts out lower dB than a straight through. The shop should have something they can weld in that will reduce the resonance that those mufflers create.

You might hear the exhaust a bit more coming out the side but that was common anyway and is a good exit so you don't have pipes sticking out the back.

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Originally posted by rizzle:
I have a 1976 F250 4x4, you have not yet come close to spending money on that truck, it will never end .

Yep, I know. I've also got a 68 Mustang that's somewhat of a money pit. It's good stuff though. It's great getting them out on the road...it takes me back.

Thanks HRK.

It does look like they did a very nice job! If you don't know who originally did the work I'd take it to an exhaust specific shop.

I do all my own mechanical work myself, but I won't do exhaust. It's a pain in the rear if you don't do it often enough and don't have a lift. If you tell them they can keep the relatively new mufflers they may knock something off the price.

Too bad they didn't put in an X pipe...that will quiet them down.

I had a 77 Ford pickup with the 400 engine. When time for a new exhaust, I called one of the muffler name brand companies. They said I should use a 2.5" single exhaust for best results

I think that'd be ideal, but I'd rather not redo the whole thing. It's sounding like just replacing the mufflers will probably get me where I'm happy.

Thanks fellas.

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Originally posted by Gustofer:
getting new ones of the right length,

In my very limited experience, therein lies your challenge in making this work right. Since you're not replacing unmolested stock pipes once those are cut off, you will likely not be able to use stock muffler and have right length. Then you get into extensions, etc. All while not wanting to move the overall architecture forward or back or you will probably luck into something rubbing or rattling somewhere.

A good shop can weld all that back together in proper alignment and it will be a once-and-done deal.

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Originally posted by HRK:

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Originally posted by Gustofer:

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Originally posted by HRK:
Yes the tail pipes can make a difference depending on where they end, if it's turn downs under the bed you'll have a louder exhaust,

So with the existing pipes that go up then down under the bed, even if I put quiet mufflers on it may not give me what I'm after? Shoot...more money....

Maybe, but think it's those Flowmasters that are your problem, they are straight through mufflers, meaning no curves and little if any sound deadening.

Flowmasters are a good muffler if you like performance and louder sound.

You want something that puts out lower dB than a straight through. The shop should have something they can weld in that will reduce the resonance that those mufflers create.

You might hear the exhaust a bit more coming out the side but that was common anyway and is a good exit so you don't have pipes sticking out the back.

I always thought Flowmasters had an objectionable exhaust tone to them.

Presuming those are Flowmasters, they have 3 models or series and they have different sound levels they are all the same length, 2.25 inlet outlet size and same placement.

So if those are 40's, and you'd have to be sure, then you could switch to the Super 50 Series but there would have to be some work done.

Link

40 - Loud Aggressive
50 Delta - Moderate
Super 50 - Mild

IT might be easier to put in an X pipe or a set of resonators in front of the mufflers.

When I checked Summit Racing they had only FLowmasters and three Walker Replacement mufflers that are Quiet flow models.

Link Summit

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Originally posted by Gustofer:
I think that'd be ideal, but I'd rather not redo the whole thing. It's sounding like just replacing the mufflers will probably get me where I'm happy.

Thanks fellas.

Personally, I’d have an exhaust shop fab me a Y pipe and ditch one side of that exhaust and keep the other side.
I’d also have them throw a high flow cat on there.
I am guessing there was some sort of catalytic converter where those straight pipes are just after the headers.

I pulled all 6 catalytic converters on my 1996 Mustang GT and one smelled like gas pretty much all the time.
Sound was nice and all along with a bit of added power but not worth the smell.

I have an appt Thursday morning with the local dealer (closest place within 90 miles to get it done) for an estimate. Hopefully it won't be too spendy. Mufflers are fairly cheap, but the $125/hr labor sucks.