What is the difference between these two early 2-in, 1-out mufflers?

Zeke · 02:57 PM

Well, I KNOW what the difference is.... the one on the right has longer inlets. The PN on it says 911 111 011 08 and it came off a '69 according to the person I got it from.

At first, I thought the one on the right would have been for the long wheel base models, but the PN is good for much earlier than that. The other one with the shorter inlets simply says 911/1.

PET says the mufflers changed in '70 to 911 111 025, IIRC. What's the deal? What fits what?

BTW, these aren't from a 912, those numbers are waaayyy different.

CORRECTION : the number(s) above should have been 901 111 011 /10 69, 901/1 and 901 111 025

Zeke · 05-16-2005, 06:49 PM

Damn, forgot the pic.

sammyg2 · 05-16-2005, 08:18 PM

The one on the left has more of a yellow tint to it.

Zeke · 05-17-2005, 05:38 AM

Come on, guys. This is important.

I know someone else who should know about this. He makes mufflers.

mb911 · mb911's Garage

I am currently getting the run around on the same thing Milt.. I have told probably 100 times there is no difference But I disagree. The tail pipe location is the only difference that I can tell The length of the inlets should be the same .. Let me know what you find out I am very interested

304065 · 05-17-2005, 08:18 AM

Hmm. . . OEM would be 901 111-011-09, no?

I'll check my PET tonight. If you don't need both, BTW Milt, I'd be interested in one for my '66.

randywebb · 05-17-2005, 10:34 AM

Functionally, the length will affect the timing and amplitude of pressure pulses for scavenging. But on a car with a muffler, that should not be very important. Perhaps PA G thought otherwise at one point...?

Harlan Chinn · Harlan Chinn's Garage

The difference lies in the width of the muffler and where the tail pipe exits the rear valence. The earlier models exit closer to the center, later models further out. My mechanic was sent the wrong muffler and after they installed it discovered that they would have to cut about a 1/2" off of the inside opening for the tailpipe to clear. Getting the correct muffler for the SC solved it all.

Zeke · 05-17-2005, 12:31 PM

Neither of these mufflers are new enough to be a '74. I thought of that, since there is more room behind the the mid year bumper. Besides, the one that has the longer inlets has a PN for a '69 and is stamped '69.

It looks to me like the tips are very close in overall lineup. The one might droop a tad, but AFA being nearer the center, it's not. They are exactly the same width and size.

Did anyone notice that the Leistritz model on the left in the last pic, and on the right at the first pic, has smooth inlets and the other has the rib? Perhaps that's the only difference, different makes for the same application.

pwd72s · 02:26 PM

A mystery to me, Milt. I can tell you that my stainless Leistritz was purchased in 1975 from the Old Valley Core Co. I just ordered one to fit my '72 that still runs factory exchangers. I gave away the "sport muffler" mod that was the reason for the change. Everything bolted right up for me. I'm just back from the garage. Including the inlet flange, I get a tape distance of 11mm, or about 4 1/3" on the bottom edge of the inlet. Meaning from where the flange meets the heat exchanger to where the inlet meets the muffler, measuring the length on the side pointed toward the ground. The stamped Leistritz number is 421-0783.
Hope this helps. If the inlets were longer? I don't think the muffler would fit well behind the license panel. (edit)...FWIW, my Leistritz DOES have a welded ridge on the inlet pipes. ????

Zeke · 05-17-2005, 03:12 PM

Paul, that's useful info. The muffler above that has the shorter inlets meaureed as you say. It was painted grey and is definately not SS. The other measures a little over 5" the way you describe, so we are not talking about much.

In the case of Ben's muffler which does not have the banana shape, that 3/4 or 7/8ths was interfering with my bumpers at the outward corners. I cut his orginal design shorter like the one above and rolled the muffler body upwards towards the motor and sent it back along with a drawing for rewelding.

I think I'm satisfied that these are both for the early cars. I sure didn't want to ship one all the way across the country only to have someone say "it doesn't fit" and make me take it back. I just today shipped a "sport" muffler to Shuie which had the ribs and the shorter inlets. I know it will fit his hot rod.

These two have been advertised on the parts BBS for a couple of days and I have some interest. They should be spocken for by tonight.

Thanks to all who took the time to evaluate these and convey their info.

Bobboloo · Bobboloo's Garage

I'll make a wild guess here. In 70' the 911 transmission replaced the 901. Is it possible that this moved the motor back ever so slightly?

Also the wheel base increased ever so slightly in 70' over the previous increase of the 69' year model. Something like a half inch. Coincidence?

pwd72s · 05-17-2005, 04:41 PM

Quote:

Originally posted by Bobboloo
I'll make a wild guess here. In 70' the 911 transmission replaced the 901. Is it possible that this moved the motor back ever so slightly?

Also the wheel base increased ever so slightly in 70' over the previous increase of the 69' year model. Something like a half inch. Coincidence?

May be a "wild" guess, but it sure makes sense to me!

silverc4s · silverc4s's Garage

Well, even if the wheelbase was 1/2" longer in 1970 [I never heard that before, what is the info source?] if the motor mounting points in the rear were not moved in the chassis the engine to muffler dimensions would not change, right?

Bobboloo · Bobboloo's Garage

Quote:

Well, even if the wheelbase was 1/2" longer in 1970 [I never heard that before, what is the info source?] if the motor mounting points in the rear were not moved in the chassis the engine to muffler dimensions would not change, right?

True, but maybe the cradle is different. I don't know, but it's a good point. Do all the HE's have the same length pipes?

As for the source on the wheel base I don't remember. I read it years ago. I'll see if I can find it.

304065 · 04:00 AM

Well, just to add to the confusion, my OTK (the legal PET) lists 911 111 025 00 as the part number through '72, and then 911 111 025 01 for -74.

If you punch the '00 into Pelican you get a Dansk! Stoddard sells a muffler that "fits" for $365, doesn't sound like the original to me!
Their '01 is $1400. . .

Things keep getting curiouser and curiouser.

oldE · 05-18-2005, 07:30 AM

Bobby,
There was a major wheelbase extention in the '69 model year, (57 mm, or 2 1/4 inches), to 2268 mm. From the 1973 model year onward, the wheelbase was extended by an additional 4 mm, (3/16 inch) to 2272 mm.
Les

304065 · 05-18-2005, 07:48 AM

I have never seen any data that suggest that the wheelbase extension affected the distance between the engine crossbar and the muffler location, which is strapped to it. On my '66, they are right next to each other; same on the '71.

However, what DID change was the heat exchangers in 1967-- and that might account for the different lengths in the muffler inlets.

pwd72s · 05-18-2005, 09:33 AM

Bobby was also referiing to a transmission change...could that be a factor? '72 was the first year of the 915 transaxle..

Bobboloo · Bobboloo's Garage

The 4mm change in 73' was what I was refering to. I just couldn't remember the year. I was thinking it was in 70'.

The HE change in 67' is the answer that makes the most sense.

In reading Milt's post I thought the muflers were made in 69' and later respectively. In re-reading I see he doesn't state a production date for the muffler with the longer inlets but that it's part number is actually much earlier. Oops.

Anyway,

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