AAR Muffler

[AAR#2]

. . . AAR - T/A exhaust layout (with black mufflers & "flats" toward the centerline)
for the mufflers & "megaphones" to be square with the rocker panels, they sit lower than typical factory dual exhaust resonators

the tips had a "bump" to align with a "notch" in the muffler outlet - the attached NOS muffler & tip pics cannot both be accurate, as there is no way to mount them to place the visible RH "bump" in the "notch" of one of the mufflers

was the muffler inlet a welded connection on factory installations? 

The notches in the muffler was not for the tip but to accept a welded key on the aft end of the head pipe. The "bump" is commonly called a spud and when inserted into the non-notched side of the exhaust acts as an insertion stop. All connections were made by mechanical means, no welding.

[cuda dad]

. . . AAR - T/A exhaust layout (with black mufflers & "flats" toward the centerline)
for the mufflers & "megaphones" to be square with the rocker panels, they sit lower than typical factory dual exhaust resonators

the tips had a "bump" to align with a "notch" in the muffler outlet - the attached NOS muffler & tip pics cannot both be accurate, as there is no way to mount them to place the visible RH "bump" in the "notch" of one of the mufflers

was the muffler inlet a welded connection on factory installations? 

This makes more sense to me.  The notch in the mufflers pictured is on the flat side so it cannot be for the outlet pipe.
The notches in the muffler was not for the tip but to accept a welded key on the aft end of the head pipe. The "bump" is commonly called a spud and when inserted into the non-notched side of the exhaust acts as an insertion stop. All connections were made by mechanical means, no welding.

[three two barrels]

Here are some pictures of the 173 mile Challenger T/A, notice the big ugly screw on the strap!

[anlauto]

Some great reference photos for @muscleonly 

[muscleonly]

Those are some great shots showing how the strap and hanger fit together, thanks so much

[6Pack70]

Ok guys and gals,  it took me a while but I finally found my photos of the word INLET on the NOS T/A mufflers.   Either these NOS over the counter mufflers are made incorrectly (which would be my guess) or the flats would go to the frame rail side.   Looking at the original mufflers on the yellow low mile T/A, those notches are on the OUTLET side not the to locate the headpipe inlet.   I think the low mile T/A would be indicative of how assembly line T/A mufflers really were.... not like the NOS over the counter ones.   Study my pics very closely and look at the word INLET and then think about how to mount these mufflers.  The flattened areas will end up towards the frame rails.   Another example of NOS parts not being the same as what was installed on the assembly line.   

[6Pack70]

Unless I'm seeing incorrectly, the word INLET is closest to the side without the notch on the boxed NOS mufflers above.   These look like correctly made later NOS t/A mufflers to me.

[anlauto]

Surprised they're still making them in 1979

[Floyd]

Most of the NOS mufflers I've seen over the years are dated 1979.  I've also seen mufflers dated 1975, but much less frequently.  Here's a set I have with the 1975 date.  No "inlet" stamp.