Topic: stock exhaust

[Justin]

 Where would I be able to find the stock exhaust setup for my car? I know Walker makes the "Y" part that goes from the Catalytic convert to the mufflers. I can't find the same Cat or the "Y" pipe portion that comes from the manifold collectors to the Cat itself. Anyone have any suggestion?

1978 Trans Am 400 4 Speed

[Justin]

This is the style I am trying to duplicate. I pretty much need the y section from the exhaust manifolds to the mufflers including catalytic . Maybe someone even has some used stuff. I don't care. It wont be on for long.

[Tin Indians Rule]

Justin, Im not an expert by any means on the W72 cars (or really any of them) but I can't ever recall seeing a factory splitter after the catalytic converter going into dual floor board mufflers. That piece must be custom and I'd guess any qualified muffler shop with a pipe bender could duplicate it.

I's guess the y coming out of the manifolds was a custom piece too???

[Justin]

Well the splitter pipe coming after the cat I CAN find everywhere. Oreilly has it,autozone,Rockauto and advance auto all have that splitter so I would be forced to assume(because I was not alive in 1978) that it was stock. I can not find anythig on that style cat or y pipe coming from manifolds.

If anyone does have any pictures of original 1978 W72 set up I would be more then happy to be taught a little about it. All I can go by is what the inspection books say which is "manifold to y pipe to single catalytic converter to split pipe with dual muffler and dual out tips".

[Tin Indians Rule]

usually by the time my cars made it to me they were already butchered with headers, straight pipes, etc.... Not really seen many all stock F-body exhaust systems.

[Justin]

http://www.oreillyauto.com/site/c/detail/WAL0/42546.oap?year=1978&make=Pontiac&model=Firebird&vi=1250424&ck=Search_02422_1250424_750&pt=02422&ppt=C0022

[eroc022]

Justin, Im not an expert by any means on the W72 cars (or really any of them) but I can't ever recall seeing a factory splitter after the catalytic converter going into dual floor board mufflers. That piece must be custom and I'd guess any qualified muffler shop with a pipe bender could duplicate it.

I's guess the y coming out of the manifolds was a custom piece too???

it was stock..... y out of manifolds was stock as well......

my question is.... why are you going back to stock exhaust? CA law? otherwise you could run duals with newer catalytic converters and pass the emission test.... just lean out the carb the day you have inspection.....

[Tin Indians Rule]

I see this was original for 79 and newer??

Did the 78 W72 cars get this as well or single pipe back to single muffler?

[eroc022]

im almost positive my 77 had it....but  i know 78s had it, as its in the service manual.... 77 if I could find it, I could say so or not.. but again, pretty positive my 77 400 had it.... and aside from paint job it was all original car.....

[eroc022]

only pontiac 400 engines in 78 got it by the way, vin u,l, and k got the single in dual out

[oboogie80]

On my 78, 400 it has the Y pipe from the manifolds to a  Cat converter to a single inlet (Transverse muffler) Dual out. I replaced the transverse and split it after the cat converter some time ago. I'm hoping to install a true dual cat back system (X crossing) this spring. I wouldn't consider stock unless I was showing it.

[eroc022]

seems like for the 400s it was optional... I am guessing the W72 motor had it... and optional for the rest....

[Burd Turd]

Heres my orig crossover pipe, very thick steel, and here is my orig cat, and the cat hanger brkt.



I didn' have this set up, this was the "dual exhaust" for 78, I had the muffler w/ 3 holes in it.

[Burd Turd]

I found these in the 78 manual, there are alot of detailed photos of the exhaust systems in there,

[hada76]

still say its amazing these cars had any pep at all with these setups