79 Exhaust

[roadking77]

I suppose I could do some research but figure I would start here. I am looking for exhaust information for my Tenth Anniv. Car.  I pull up as many images as I can to look at details of these cars to help guide my restoration. I am getting close to purchasing an exhaust system. I talked with the guys at Pypes and they said the transverse muffler actually gives a bit more HP than the duals. I have duels on my 77 and was considering transverse just to see what the difference in sound and performance will be. Looking at what are supposed to be original, low mileage cars I am seeing a single cat, duel exhaust mufflers after the cat. I havent seen one yet with the transverse mount. Does anyone know exactly what came from factory? Im not overly concerned about original as I will def not install a cat, but if it could look close would be good to me.

[Jack]

Kerry, my advise would be to go with true dual exhaust and ditch the cat.

[Warren Seale]

Original owner here.  In 79, and 78 as well, the WS6 pkg included the two turbo mufflers.  Otherwise, you got the transverse muffler.  I live in FL and as a result there is no vehicle inspection so I eliminated the catalytic converter and changed the manifolds on the 403 to the Thornton small block Olds manifolds that eliminates the cross over port.  I kept the dual turbo mufflers.

[Blkjack]

Gardner Exhaust Systems which specializes in restored muscle cars seems to prefer their transverse system of F bodies. They are on Facebook if you want to check them out. They have some clips too on their website. FYI your car originally came with a single cat and to resonator like mufflers not Turbo mufflers

[5th T/A]

Kerry,

I believe you are trying to stay as close to stock as possible on your restoration. I got this information from Rocky Rotella's book "The Definitive Firebird & Trans Am Guide" If it sounds like I am plugging his book, I am. Its great reading for anyone interested in 2nd Gen Firebirds, but for anyone restoring or working on one its a great resource.

I think you said your car came with the TA 6.6 engine and a four speed. As the picture shows you had a CAT splitting to two mufflers under the rear seat.

The factory style CAT is no longer available and I doubt the Y pipe is either. Depending on where you live, you may be required to have a catalytic converter.  I think modifying an exhaust system from OEM is one of those things that most people don't really ding you on as long as you stay away from headers. Regardless of what you decide I would try to stick with the split tail pipes.


IMG_8491 by Lawrence Alexander, on Flickr

IMG_8490 by Lawrence Alexander, on Flickr

[roadking77]

Thanks All. That is the settup I keep seeing. A bit disappointing though as I had really wanted to go the transverse route. I may take the exhaust off the 77 and put it on the 79 and re do the 77's exhaust. I do not need the cat converter, def wont be using that. Also a bit of a deviation but plan on using ram air exhaust manifolds.

[5th T/A]

I am with you on the transverse muffler. On my 80 I installed a stock 1974 Super Duty exhaust system, because it had 2 1/2” pipes from the manifolds to the muffler. I did retain my stock splitter tail pipes because they were in great shape. I also used Ram Air exhaust manifolds. I like the exhaust sound of early 2nd Gen Firebirds with the transverse muffler. I was under the impression the transverse muffler cost horsepower over separate mufflers. When you spoke to Pypes were they referring to their transverse muffler or OEM? Also the factory produced several different types of transverse mufflers depending on the year and engine size. They had different baffling and pipe sizes. Honestly I was more concerned with looks and sound versus max HP.

[737driver]

I really like the transverse setup. I ha e used it twice and have been really happy with all aspects. I install over the axle takes a little bit of work but nothing to really complain about. I really like the more ground clearance the transverse muffler offers.
Jim

[Wallington]

I think either of the Pypes systems requires work around the rear axle end and for correct location of splitters and hangers to use factory locations. I'd imagine they have a crossflow muffler option, really twin mufflers in one case, that far exceeds performance than a 40 year old stock version.

[roadking77]

Yes Pypes.  I have a pypes system, dual mufflers, x pype, no catalytic. I think its 2.5" with ram air manifolds on my 77. Motor (auto trans) is slightly warmed over (guessing around 300+hp) and it runs and sounds fantastic. I have no problem at all with this settup, other than there is a slight drone, best I can describe it. From what I have been reading it may be the x crossover.

I was speaking with the fellow from Pypes at Carlisle regarding a system for my 79 400 4sp car. He said that their single transverse muffle actually allowed a bit more HP than the dual settup. This completely surprised me. I had assumed that the single was how they came and figured on using that. My biggest curiosity is how the 4 speed car will sound and perform compared to the auto. Hence why I was wanting to use a different exhaust system.

[formula jg]

If you want to maintain that OEM exhaust appearance when viewed from the rear of the car and your going the dual muffler/resonator route then be sure to install the mufflers slightly angled with the higher side up by the driveshaft. It’s difficult to see from Lawerence’s pic but the mufflers are not level.

[Bayou_Flyer]

I just got my car home, 75 Formula 4spd, after having the Pypes 2.5 transverse system installed. Has a great sound, everything is tucked up nicely. I did downpipes from stock manifolds to the tail pipes.

[roadking77]

Are they stainless?  I have heard that stainless has a distinct 'ting' to it. Thats another thing I think I am going to change on the next one. I will use plain steel.

[FormTA]

I too have the stainless pypes transverse set up. Now it's on the LS engine but I really like it. Fairly quiet but sounds awesome at high RPMs and idle, no annoying drone either. It fit well but the muffler hangers could be better, they're just universal hangers. Someday I may change them to something more stockish.

[tajoe]

Like mentioned above, eng. option determined TV or fake duals. Had this V-6 79 bird many yrs ago, and it had the TV muffler set-up.