Original mufflers question for HP engines

[Mariposa Mike]

2 1/4 inch in front. But room??? See more pictures. It's busy under there.

 

[AR67GTX]

I would avoid using the Accurate resonators like used on 69 Hemi cars. A friend of mine has a restored 69 Hemi Roadrunner with a full Accurate system and his rusted through in about 3 years and 700 miles. If you use them I would sure drill a small hole in the low point to allow any condensation to drain.

 

[Some Car Guy]

the borla xs pro will out flow the big super turbo mufflers they are shorter too.

Of course. Isn’t in the discussion of quiet stuff. The ultraflos are the highest on the chart for that matter.

 

[gtxrt]

Of course. Isn’t in the discussion of quiet stuff. The ultraflos are the highest on the chart for that matter.

the point was if you want quiet the quiet flow ss mufflers are quiet plus flow a little better than stock. then there was talk about more flow with the dynomax super turbo. I said if you want more flow then the quiet flow than go with the borla because they flow better then the dynomax plus no drone and a better sound without being too loud. the ultraflos are crazy loud. read my first post #16

 

[Mariposa Mike]

The Accurate tech is back and I spoke with him today. He has been doing this work for several decades. After having me check my exhaust manifolds to determine if they are stock (they are) I sent him pictures of my current system and this time I measured the pipes with a caliper instead of holding a tape measure up and guessing. The entire system is 2.5. He also mentioned the system is quite old and using pipe that is longer used by anyone due to how it degrades and sounds. Tom says the original system was 2" as others have posted, no H pipe and 1 7/8 tail pipe for the 361 and 383. He designed a system some 30 years ago that upgrades to 2 1/4 front to rear. With factory type hangers. No H pipe.

This is all to give a factory appearance and sound but with improved exhaust relief for a 383B engine. Also mentioned was how close the rear pipes are to the fuel tank. 1/8-1/4 inch along the side seam on both sides. That has not been a problem over the years but could be if something was to hit the pipes and bend them in.

Accurate has a bolt on system that returns it to stock appearance except for the increase in size and gives it a better sound than stock but without the drone. I asked about maybe upgrading to a muffler that might give it a little more sound. He does not recommend that due to the design of the 66/67 Chargers being so open inside with the drop down divider in the truck for increased inside storage. 68 and up are a different interior and story. They have sold these systems with no complaints. And he has not modified it in 30 years. He mentioned Ford and GM does not have this issue since they are not unibody cars that help resonate sounds to the interior. MOPARs need to have the correct hardware to mount the system just like they designed back in the 60's.

As I am trying to keep this car as stock as reasonable possible...not for judging...but just because I like to represent the car as it was built back in the day, I'm in between a rock and a hard place. The cost of the system is $1221 plus $340 (ouch) shipping due to oversize. $1500-1600 is a lot to spend on an exhaust system but it would return it to stock. I could gamble and put hemi mufflers on but Tom says many people have chased the drone and not been successful. It would also replace a system which is rather unsightly and possibly rusting out in places, or soon will.

Given the difference between the cars and systems in replies here, this might be more of an issue for the 66/67 Chargers than other cars mentioned. My getting schooled on this issue is good info but the tuition is pricey. I hope all this is helpful and interesting to others on this forum. Now I just gotta make the decision. And maybe find a reason to make a drive to Oregon and deny FedEx the terrible shipping charge. Lets see....CA fuel being next to most expensive in the US....HMMMM probably about the same money driving 450-500 miles from Central CA. Might save $100.

 

[gtxrt]

what is wrong with Waldron exhaust i used them on my Newport.

 

[Don Frelier]

The Accurate tech is back and I spoke with him today. He has been doing this work for several decades. After having me check my exhaust manifolds to determine if they are stock (they are) I sent him pictures of my current system and this time I measured the pipes with a caliper instead of holding a tape measure up and guessing. The entire system is 2.5. He also mentioned the system is quite old and using pipe that is longer used by anyone due to how it degrades and sounds. Tom says the original system was 2" as others have posted, no H pipe and 1 7/8 tail pipe for the 361 and 383. He designed a system some 30 years ago that upgrades to 2 1/4 front to rear. With factory type hangers. No H pipe.

This is all to give a factory appearance and sound but with improved exhaust relief for a 383B engine. Also mentioned was how close the rear pipes are to the fuel tank. 1/8-1/4 inch along the side seam on both sides. That has not been a problem over the years but could be if something was to hit the pipes and bend them in.

Accurate has a bolt on system that returns it to stock appearance except for the increase in size and gives it a better sound than stock but without the drone. I asked about maybe upgrading to a muffler that might give it a little more sound. He does not recommend that due to the design of the 66/67 Chargers being so open inside with the drop down divider in the truck for increased inside storage. 68 and up are a different interior and story. They have sold these systems with no complaints. And he has not modified it in 30 years. He mentioned Ford and GM does not have this issue since they are not unibody cars that help resonate sounds to the interior. MOPARs need to have the correct hardware to mount the system just like they designed back in the 60's.

As I am trying to keep this car as stock as reasonable possible...not for judging...but just because I like to represent the car as it was built back in the day, I'm in between a rock and a hard place. The cost of the system is $1221 plus $340 (ouch) shipping due to oversize. $1500-1600 is a lot to spend on an exhaust system but it would return it to stock. I could gamble and put hemi mufflers on but Tom says many people have chased the drone and not been successful. It would also replace a system which is rather unsightly and possibly rusting out in places, or soon will.

Given the difference between the cars and systems in replies here, this might be more of an issue for the 66/67 Chargers than other cars mentioned. My getting schooled on this issue is good info but the tuition is pricey. I hope all this is helpful and interesting to others on this forum. Now I just gotta make the decision. And maybe find a reason to make a drive to Oregon and deny FedEx the terrible shipping charge. Lets see....CA fuel being next to most expensive in the US....HMMMM probably about the same money driving 450-500 miles from Central CA. Might save $100.

Sorry but I disagree with much of what you were told. To me the front section of your exhaust looks fine.
I'm not sure your tailpipes are a duplicate of the original. They appear to bend upwards after the tank and Im pretty sure mine didn't do that.

All I can say is I have a somewhat similar setup with 2-1/4" headpipes and a 2"H.
I have hemi mufflers and tips and it's pretty much perfect for sound no drone.
But, I have superbee tips on it which do help compared with the factory turndowns which don't get you beyond the rear bumper.

Why not just change the mufflers and see the results?

 

[gtxrt]

what helps most drone is going down to 2.25 tail pipes over the 2.5 tail pipes.

 

[Mariposa Mike]

I could try changing the mufflers but if it did not work then I'm still looking at a big payout. Have not priced just the mufflers yet. And then I still have the old pipes which do show some age and declining condition. Plan to do a little more aggressive cleaning on those to see if they NEED replacing and take another look at the position of the rear pipes next to the fuel tank. And then changing mufflers...several types have been mentioned, which ones would offer the best chance of getting rid of the drone. Probably the Hemi. There is another shop about 40 miles from me that has an old time experienced man working there. I'm curious what he would have to say listening to this issue.

I do appreciate all the suggestions/opinions. Eventually I will get this solved. What others have experienced is valuable information.

 

[33 IMP]

@Voetom has forgotten more about mufflers than 95% of us know. I've paged him for his opinion. I would follow his suggestion.

 

[Mariposa Mike]

Thanks. Maybe others following this post will get something from his opinion as well. And I hope the 66/67 Chargers are not a unique animal when it comes to mods from original. Looking at other body styles similar to the Charger would likely be similar. Like the 67 Barracuda, etc.

 

[Mariposa Mike]

Drove the car yesterday on the longest drive since I purchased it in June. What I noticed is that if I can stay out of the 50MPH speed, nearly impossible with all our two lane roads and tourists, the sound is not too objectionable. I live in rolling hills/mountains with very few opportunities to pass. But once in the 55 and up range it's not too bad. Our archaic road speed limits that have not changed in 70 years have kept the 55MPH. Also driving up steep hills gets the car in the RPM range that brings out the drone. If I can get to 60 and above it diminishes a lot. Just wanted to add first hand experience since I have only been able to drive locally before now. It might be a minor change is all that's needed. Such as the mufflers. Or maybe live with it. Looked on line at a couple companies and don't see the Hemi muffler in a 26" length yet.

The car drove very well except for the minor excessive steering wheel play. And it probably needs shocks. Will start looking into the availability of those.

 

[33 IMP]

Drove the car yesterday on the longest drive since I purchased it in June. What I noticed is that if I can stay out of the 50MPH speed, nearly impossible with all our two lane roads and tourists, the sound is not too objectionable. I live in rolling hills/mountains with very few opportunities to pass. But once in the 55 and up range it's not too bad. Our archaic road speed limits that have not changed in 70 years have kept the 55MPH. Also driving up steep hills gets the car in the RPM range that brings out the drone. If I can get to 60 and above it diminishes a lot. Just wanted to add first hand experience since I have only been able to drive locally before now. It might be a minor change is all that's needed. Such as the mufflers. Or maybe live with it. Looked on line at a couple companies and don't see the Hemi muffler in a 26" length yet.

The car drove very well except for the minor excessive steering wheel play. And it probably needs shocks. Will start looking into the availability of those.

Have you determined what rpm the drone is the worst? Does it drone at the same rpm in a lower gear?
Mind you, I have not personally tried them...., but if you search Jones Exhaust at summit, you will get about eleven pages of every muffler size and type imaginable. Stainless too, at pretty good prices.
I have a 24-26" case muffler on my opel, (I'm not at the car right now, so I can't say for sure), but it's a magnaflow straight thru 3". It's quiet for what it is, and doesn't drone, but probably a a bit louder (or more thana bit) than a hemi muffler.
Edit: I was wrong... eighteen pages.

 

[Mariposa Mike]

I'll take a look. I tried Summit/hemi and only saw four mufflers listed but probably my using the Charger as a search limited my response.

 

[33 IMP]

I'll take a look. I tried Summit/hemi and only saw four mufflers listed but probably my using the Charger as a search limited my response.

Do you want 26 over all length, or 26" case length?
Also, check out the thread below "fixed my exhaust drone" with helmholz resonators.
Jones Q524B quiet tone 2.5 in/out, 19.5 case, 25 oal.

 

[Mariposa Mike]

26" overall. That is what would be a direct fir with the pipes on the car now. I already looked at the resonator thread. I do not have room for those with the current pipe configure.

Just looked on Summit under the Jones mufflers. They don't say much about the muffler other than high flow. Or magnum. Saw a 24" and there are a lot of mufflers so probably one in the correct length but no descriptions. Not sure what they would sound like. Might be like throwing darts at a target. Have you used them?

 

[33 IMP]

I have not. I've got giant fm's that I'm happy with, but would not buy again ($250 ea!), hooker aeros, fm on my dually, and long skinny magnaflows on my opel.
What I like about the Jones, they have several 3.5 in out, at about half the price of everybody else.

 

[gtxrt]

I like the walker quiet flow. they flow a litttle better than a stock muffler and have just a slight sound. no drone. they are between the walker fx sound and the walker big dynomax.

23 inch total length quiet flows like I have on 3 cars just add 3 inches or whatever you need with the extra pipe. better flow then stock just a little tone and no drone what more do you want for a nice driver.

 

[Mariposa Mike]

Are those 2.5 in and out? They look nice. I can look up the numbers you have in this post to check fitment and price/availability. I will still need to sand on my existing pipes a little to make sure they are going to last. Maybe won't have to change them out. I believe they are okay.

Yesterday when filling the tank at a station an older couple next to me was looking at the Charger and mentioned it brought back good memories from when they saw these in 60's/70's. When I fired it up I heard her say "Now that's what a car is supposed to sound like". Would not like to lose that tone/rumble but the drone...the drone can go.

 

[gtxrt]

Are those 2.5 in and out? They look nice. I can look up the numbers you have in this post to check fitment and price/availability. I will still need to sand on my existing pipes a little to make sure they are going to last. Maybe won't have to change them out. I believe they are okay.

Yesterday when filling the tank at a station an older couple next to me was looking at the Charger and mentioned it brought back good memories from when they saw these in 60's/70's. When I fired it up I heard her say "Now that's what a car is supposed to sound like". Would not like to lose that tone/rumble but the drone...the drone can go.

2.25 in and out