[JUDGE3]

Did the 1979 TA use true dual mufflers as original exhaust?

[Skip Fix]

The Pontiac motor ones did as they had the 220 HP motor.78 the 180 hp had a transverse muffle the 220 hp had the dual muffler. All used a single catalytic convertor.

[muscle_collector]

403 cars used dual resonators also. only the 301 cars had the single muffler.

[Warren Seale]

Not 100% sure about this but the dual "turbo" mufflers were used with the 403 with the WS6 option and had the single muffler without the WS6.

No car (any model) at that time had true dual exhaust once the catalytic converter went into use. The Firebirds that had the dual mufflers combined the exhaust then entered the pancake style catalytic converter then split again before the mufflers.

Warren

['ol Pinion head]

the mufflers used as part of each tailpipe on the Y pipe/twin muffler cars are very restrictive. In the early to mid 80's, I replaced quite a few stock min mufflers on late 2nd Gens with the best flowing of the time, Sonic Turbo mufflers. On my modded turbo car & on several friend's turbo T/A's & Formula's, we just ran a straight pipe in place of each of the dinky mufflers.

[JUDGE3]

I had thought they did.

I graduated high school in 1979, bought a new 1980 Trans Am. anyway, I remember that back then we thought seeing those 2 mufflers when seeing the new 79 TA'S driving up on em from behind looked very very cool. looked muscle carish.

I was contemplating a straight thru traverse muffler but I may mod to an aftermarket built in electric pump fuel tank and have seen that creates issues with a transverse muffler back there. not much room as it is.

so i'm planning the dual mufflers and searching for the quietest yet free flowing mufflers.

[77 TRASHCAN]

Those sonic turbo mufflers really sounded good to me!!!

I Have read that the pipes to the "dual" mufflers were double walled, for some reason. The inner pipe would collapse, restricting flow. I wonder if the transverse setup may have factually flowed better. The transverse pipes were 2-1/4 pipes. THey did OK on a stock engine...My car currently has a Walker replacement system, just like the stock system, except 2-1/2 pipes. I installed a home made converter "test" pipe at around 20,000 miles...with the stock crossover pipe...

[Grand73Am]

Obviously, there were no "true dual exhausts" from 1975-1981 due to the catalytic converter.

But 79's did have dual mufflers after the catalytic converter, with the dual tail pipes and chrome splitters. My 4 79 TA's with 403 engines came with dual mufflers. 3 have standard suspension, one is WS6, so WS6 or not, makes no difference. 400's had the same.

Below is a drawing of the original arrangement:

exhaust system drawing by grand73am, on Flickr

Of course, I've eliminated the converter on mine, and am running true dual exhaust from the manifolds back, using the walker tail pipe and chrome splitter pieces in the drawing. I'm using these Walker Dynomax super turbos: https://www.summitracing.com/parts/wlk-17732

[Skip Fix]

Now the Macho TAs got dual cats from the dealer!

[68ragtop]

My 1980 Turbo TA also has the dual resonators / mufflers, just like the 78 & 79 W72's have.
I kinda like the way they sound even in factory form. When I got my 79 W72 it had a "test tube" replacing the cat, but all factory otherwise & it had a bit of a rumble to it. I re-installed the factory Cat & that quieted it down a lot, but I still like the sound of it for a factory setup.
makes a little bit of noise over your typical oem exhaust system.

[jerry455]

The dual mufflers started on the 1978 W72 cars. I bought a slightly used 1978 WS6 T/A back in the early 80's with only 20,000 miles and completely bone stock. It had the dual mufflers on it. They sounded nice.