"Hemi Mufflers" - Need some Education

[TxDon]

I need some help from the OEM experts. My 67 GTX came with what were identified as "Hemi Mufflers". I remember my first 67 (38 years ago!) had similar shaped mufflers and had a great mellow sound that didn't get in the way of the radio unless you punched it. The mufflers on this car are friggin' LOUD! Forget the radio, they bark at idle and go up from there with a bad drone at 35 mph and the threshold of deafness at 60 mph and above. Looking under the car, one has the pentastar, what appears to be a date code of 9-67 and PN's 22840 and 2781300. They look stock but definitely do not sound stock, at least compared to my memory. Here are my questions:

• What do these part numbers correspond to?
• Were there different OEM mufflers for the 440 and Hemi cars?
• If they were different, was the Hemi version substantially louder than the 440 version?
• Do they make OEM appearing mufflers with internal mods to eliminate the muffling part?

Any help is greatly appreciated.

 

[super-bee_ski]

I have a set, or a set that is identical to the Hemi muffler
I'll get the part number for you.
They were (are) Longer than the standard mufflers
Mine are "Turbo Action" I believe.

A good Bud of mine is closing shop, Performance Engine Building and Balancing AND Performance Transmission, here in So Cal.
He had a few left over from a long time ago
He performed "Flow" checks with actual sensors etc.

1. P/N is the Hemi muffler
2. Different in size, the oval barrel is much longer in length
3. Hemi version was NOT louder but more deeper in resonance, and muffled, but a good sound.
4. The Turbo Action "HE" found thru extensive research flowed better than every muffler out ther, including the Flow Masters etc. (Even though the others advertised better numbers)

It is interesting to Note: The Mufflers have "built in" dimples or "extended-hump" to aid in the flow and resonate the sound waves.
I'll snap a pic for you.


PS: I bought 3 or 4 sets of Mufflers from him for $25 each.
1 set was (is) the Hemi mufflers

 

[440beep]

Layson's has your mufflers listed as Hemi mufflers. The 5 digit number looks to be the vendor code.

http://www.laysons.com/Catalog.cfm?nCatID=2855&nModelID=16&nModelYear=1969

 

[super-bee_ski]

Turbo Action has them too
As stated above

 

[texas69bee]

http://www.ecsautomotive.com/
http://www.accurateltd.com/

 

[super-bee_ski]

Okay,
The Hemi mufflers my Bud did the research on are called: Super Turbo
Currently owned by DYNOMAX
The are identical to the original Hemi mufflers

NOTE: This is nOT an opinion
He did extensive research on mufflers
His work was printed in a Muscle Car mag.
So, he did find that this muffler was identical to the original Hemi muffler
And the original "body" of the Hemi muffler is longer as evidenced in your first post.
If you will notice, my first response answered all of your concerns.

PS: I am running them on MY HEMI 70 Superbee

 

[TxDon]

Thanks. So the original hemi mufflers and probably the current repros are low restriction tuned reverse flow mufflers, should have the mellow sound I remember. The ones on my car sound like the reverse flow part is missing, more like straight thru glasspacks. Now I have to decide to keep them or not...

 

[super-bee_ski]

Yup
If you cut open the chamber the air flows in and goes straight back, hits a reinforced wall (noticeable when looking at the exterior, a large hump is visible) and bounces "forward' to another deflector (visible hump on outside) and then it flows out the back.
The larger "oval body) of the Hemi muffler helps produce the deeper sound.
The hemi style is considerably longer in length
About 25% longer.

PS" On another note:
I had to look up form a project I was working on the other day.
I could have sworn I heard the distinctive sound of a 68-70 Ford 428 Super Cobra Jet running down the road. It sounded great but as I looked up I saw a late model Chevy Pick-up
That just about gave me an upset stomach!
These idiots with their fancy exhaust in pick-up trucks think they have a Muscle Car!

 

[lewtot184]

the original hemi/440 mufflers were 2 3/8" in and out. the 2 1/2" head pipe was swagged down to fit in the muffler and the 2 1/4" tail pipe was swagged up to fit inside the muffler. dynomax makes a 2/1/2" in and out the same dimension as a stock muffler but doesn't have the corner indents like stock. it's called a super hemi turbo.

 

[super-bee_ski]

Cool
But the original hemi mufflers are quite a bit longer (oval body) over the original mufflers.

Just check the pic and you will see.

 

[lewtot184]

Cool
But the original hemi mufflers are quite a bit longer (oval body) over the original mufflers.

Just check the pic and you will see.

not sure what you mean about length. i've used the stock hemi and dyno-max hemi super turbo both on my '69rt with the same pipes and they're both the same length; 21" case i think. regular super turbos are 16" cases.

 

[emore]

The real Hemi mufflers were not longer than the mufflers that came in a 440 car(GTX) or a 383 Roadrunner. You could swap out your stock mufflers for a set of Hemi muffs.Not only did my brother do it on a 68 Runner, I did the swap on my 68 383 Charger. The reproductions that used to be available through some of the Mopar vendors were made by Gorliech or Walker.

 

[lewtot184]

The real Hemi mufflers were not longer than the mufflers that came in a 440 car(GTX) or a 383 Roadrunner. You could swap out your stock mufflers for a set of Hemi muffs.Not only did my brother do it on a 68 Runner, I did the swap on my 68 383 Charger. The reproductions that used to be available through some of the Mopar vendors were made by Gorliech or Walker.

back in the day i did what your brother did to my '68 road runner.

 

[super-bee_ski]

LOL
They are LONGER....
Length of the BODY

LONGER
I have a set
Compared to a conventional muffler's "BODY"

- - - Updated - - -

They sure were
That is why its call the Hemi muffler

- - - Updated - - -

Lew,
what Mufflers do you have on YOUR Hemi?

 

[lewtot184]

i don't have a hemi. it's a 69 r/t 440 but uses the same muffler. i'm currently using a set of older repops. i did have a set of super hemi turbos on the car and they were the same length as the hemi repops; with the exception that they were 2 1/2" in and out. when i bought the car in '85 it had the original exhaust system on it, (i still have the h-pipe and tail pipes) and the repops were the same as the originals. i took the repops off for awhile and ran the dyno-max super hemi turbos. when i put the car back stock i put the repops back on. the case length was the same on all 3 mufflers.

 

[TxDon]

PS" On another note:
I had to look up form a project I was working on the other day.
I could have sworn I heard the distinctive sound of a 68-70 Ford 428 Super Cobra Jet running down the road. It sounded great but as I looked up I saw a late model Chevy Pick-up
That just about gave me an upset stomach!
These idiots with their fancy exhaust in pick-up trucks think they have a Muscle Car!

Hey that's normal here in Texas. One of my other cars is a 1963 Oldsmobile Starfire that needed new pipes. My memories of the GTX exhaust note were so good that I told the muffler shop to build me a "Hemi" system, they came up with the crossover pipe and big turbo style mufflers and nailed the mellow sound perfectly

 

[super-bee_ski]

Looks cool

Texas does everything better!

Hoping to leave this DUMP called "The Golden State" someday
Texas is on my shopping list.

 

[440beep]

boy oh boy, you guys are really making me want to ditch my Flowmaster 50s for these Hemi mufflers if they are that great sounding.

 

[lewtot184]

i like the sound of the originals and repops but they're 2 3/8" inside. the dyno max super hemi turbos are noisier and 2 1/2" inside. both are the same size bodies.

 

[440beep]

Oh, that's right. They won't work then with my 3" exhaust.

i like the sound of the originals and repops but they're 2 3/8" inside. the dyno max super hemi turbos are noisier and 2 1/2" inside. both are the same size bodies.