Is the OEM GNX exhaust different from a GN exhaust?

mikec1969

Member
Hi guys,
A friend of mine is currently working on GNX 432 in his shop. It's a 17K mile car with no mods. He needs some exhaust info. Any info I could relay would be appreciated. Thanks. Mike C.
 

chopped39

Well-Known Member
Does he want to change exhaust? Factory gnx has 2 mufflers due to rear suspension. Gns had 1. systems like flowmaster i dont think will fit. I know ATR made a special system for the gnx. It used the same mufflers but differant piping.Give finishline performance in naperville a call .they do awesome work. they are not cheap.But I would not let a regular muffler shop touch that car
 

BlackMetal

Active Member
Like chopped said, stock GN exhaust is one muffler with dual tail pipes but the GNX was a true dual exhaust with 2 mufflers. Can definitely hear a distinct difference between a GN and a GNX if you've ever heard them in person. Unfortunately I don't have exact info about the GNX exhaust, someone in these forums probably has detailed information and will post in here eventually.
 

mikec1969

Member
Thanks for the responses. I had the priviledge of driving 432 yesterday and you can definitely hear the difference in the exhaust. The story of the car is interesting. The owner bought the car in 1989 with under 1000 miles. I believe he gave $27,500 for the car. A couple of years ago he passed away leaving his entire car collection (a very impressive one by the way) to his wife. My friend knew the owner for years, they were good friends. Since his death the wife has been driving the car once in a while. She wanted some normal maintainence items done when she brought it in. She also wanted the power antenna fixed (no surprise) and the left rear exhaust pipe has rust holes in it. As far as not letting any muffler shop work on this car. I couldn't agree more. My friend is a 30 year GM tech and also a tech advisor for a resto shop in Lagrange, IL his specialty is Pontiacs, but he knew we could all help him with the Buick stuff. Believe me the car is in good hands. His goal is to find this exhaust part NOS, I have the original GM part number and I'll post it later today. Also, is it true all GNX's had both doors repainted? Let me know. Thanks. Mike C.
 

XRated

Is that a Monte Carlo?
I am also having to replace my original exhaust. I really didn't want to but the mufflers are rusting on the inside and I wanted to be able to preserve my original exhaust in one piece. I ordered my replacement from Kirban's this week. From what I've found they are the only supplier for an exhaust kit that fits the GNX. As far as I know the other "GNX" type systems will not fit because of the rear suspension modifications.

I'm sure there are some NOS exhaust parts around, but I'll be they'll be hard to find.
 

GNXcess

Senior Member
Greetings,

To answer your thread, the exhaust was different for the GNX. The inner corners of the mufflers were actually bashed in with a hammer to clear the suspension (this is the quick way to tell whether the exhaust is actually original to an X).

As far as "all the doors repainted" that is simply not true. While there were a number of factory and dealer redos for less than stellar paint, the blanket statement that "all" were done is demonstrably false.

Driver's side P/N: 25513005
Pass side P/N: 25513006

Good luck!
Doug
 

mikec1969

Member
Thanks for the parts #'s. I'm looking for the driver's side GM #25513005. Does anyone have a line on one? Let me know. Thanks. Mike C.
 

samgauto

Member
I always heard that the GNX and the 1987 Olds 442 had the same exhaust system however I just received an old dealership G Body Oldsmobile Parts & Illustration Catalog and the 442 muffler tailpipes are indeed different part numbers. Muffler w/tailpipe RH is 22526204. Muffler w/tailpipe L/H is 22526205.
 

Turbo6inKY

Short Guy
I always heard that the GNX and the 1987 Olds 442 had the same exhaust system however I just received an old dealership G Body Oldsmobile Parts & Illustration Catalog and the 442 muffler tailpipes are indeed different part numbers. Muffler w/tailpipe RH is 22526204. Muffler w/tailpipe L/H is 22526205.
The GNX used the 442 mufflers with one corner bashed in as mentioned before. But the piping is different to clear the torque arm and panhard bar.
 
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