1975 c3 exaust
Thread Starter
5th Gear
Joined: Oct 2021
Posts: 5
Likes: 1
1975 c3 exaust
I’m looking for some guidance on a nice sounding exhaust system for a 1975 C3. My car is very original and I’d like to keep it as original/stock as possible. I’d like to get a better sound than just the stock sound. Would something like “glass packs” be recommended? Also, is it a bad thing to get rid of the catalytic converter when trying to maintain originality?
Melting Slicks
Joined: Aug 2013
Posts: 2,180
Likes: 107
From: S Fla
Hi Bob...would depend if you wanted to keep it all original for NCRS judging. I used to go to Midas for the mufflers on my 73 back in the day. The gold mufflers looked pretty cool under thee car. Other wise check out Borla, Corsa or Magnaflow, lot of choices in the after market.. 75 has one cat and then splits off to duel from there, if you are considering removing the cat think about replacing it with a real duel exhaust system. All depends on your end game.
Race Director
Joined: Oct 2008
Posts: 19,216
Likes: 1,671
From: Long Island
Just be careful with your choice, some "muffler" systems can make the inside of the car unbearable. The interior resonance can cause a very unpleasant ride.
If you do a lot of cruising, stock / almost stock is better, ESP if you have a female with you.
There are numerous threads on the mufflers, I would suggest you read them. Also if there is a local corvette club - ask fo a ride and talk to members to get the opinions.
If you do a lot of cruising, stock / almost stock is better, ESP if you have a female with you.
There are numerous threads on the mufflers, I would suggest you read them. Also if there is a local corvette club - ask fo a ride and talk to members to get the opinions.
Advanced
Joined: Jul 2021
Posts: 56
Likes: 14
From: Charlotte Tennessee
I just finished putting a Magnaflow system on my ‘69. Really like the sound. Not loud, but a nice tone. Haven’t done much driving yet, but no noticeable resonance in the car. They recommended professional installation which I ignored and now I understand why they would recommend it. I would too now, not because it’s difficult to do, but rather because the instructions are minimal and there are some things that need massaging relative to getting sufficient ground clearance. I’m impressed with the quality of the system.
Instructor
Joined: Feb 2007
Posts: 114
Likes: 18
From: McKinney TX
I have a '74 so my exhaust is a full dual without catalytic converters. I always considered the best sounding mufflers to be the stock units on my '63 but even years ago I was unable to find anything that even came close to that sound. I never liked the MagnaFlows and similar competitors so for some time I just ran generic Midas mufflers. Some time ago I discovered someone had reverse engineered the original GM off-road N11 muffler. As I recall, at that time they were sold exclusively through Corvette Central. That may no longer be true, I don;t know. In any event, I've been happy with them. I should add however that I upgraded the exhaust to 2.5 inch diameter coming out of 2.5 diameter rams horn exhaust so I've essentially replicated on my '74 what I had previously known on a C2. I also insulated the entire interior under the carpet both to minimize noise and especially heat. Without the insulation these mufflers may be a bit loud for you. Also, I don't know how well they will fit unless you revert to a full dual exhaust.
Le Mans Master
Joined: Jan 2007
Posts: 7,994
Likes: 3,334
From: Omaha NE
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2023 C3 of the Year Finalist - Unmodified
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2020 C3 of the Year Finalist - Unmodified
'75 was GM's 1st cat and it has the same flow rate as a box of frozen peas.
I went with the Corvette Central Magnaflow dual system with 2 1/2" pipes years ago.
No more Y-pipes and the sound is not much louder than stock.
Installation would of been a lot easier with a rack, but I was still able to get-er-done...
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Pro
Joined: Aug 2009
Posts: 704
Likes: 503
From: Temple, TX
Only if you're going NCRS. Otherwise ditch it!
'75 was GM's 1st cat and it has the same flow rate as a box of frozen peas.
I went with the Corvette Central Magnaflow dual system with 2 1/2" pipes years ago.
No more Y-pipes and the sound is not much louder than stock.
Installation would of been a lot easier with a rack, but I was still able to get-er-done......
'75 was GM's 1st cat and it has the same flow rate as a box of frozen peas.
I went with the Corvette Central Magnaflow dual system with 2 1/2" pipes years ago.
No more Y-pipes and the sound is not much louder than stock.
Installation would of been a lot easier with a rack, but I was still able to get-er-done...
...Attachment 48335309
Attachment 48335310
Attachment 48335311
Installed, but position not finalized.
Attachment 48335312
Burning Brakes
Joined: Dec 2017
Posts: 1,043
Likes: 414
2023 C3 of the Year Finalist - Modified
My opinion, electric cutouts are a great thing to add! You can have a quieter cruising style muffler, avoiding any loud drone, but push a button and have very loud open header noise whenever you want it.
I have a 2.5 inch dual setup, H-pipe with two dynomax single chamber mufflers and electric cutouts right after the headers.
I have a 2.5 inch dual setup, H-pipe with two dynomax single chamber mufflers and electric cutouts right after the headers.
Instructor
Joined: Sep 2021
Posts: 140
Likes: 70
From: North Texas
I'm looking at getting new mufflers as well. My 75 has headers and a full dual exhaust with flowmasters (no cats) and it's really unbearable in the car. At certain RPM the whole rear deck area buzzes and vibrates like crazy. I'm wondering if quieter mufflers will alleviate some of that or if I've got something loose back in there. I've getting tires done on Saturday and may just stop by Midas after that to see what they can do for me without me spending an arm and a leg.
I must be getting old when I want my car to be quieter instead of louder.
I must be getting old when I want my car to be quieter instead of louder.