Need Opinions - My Hybrid Exhaust System

[paul67]

When I bought my 1967 in 2003 it had an underbody chambered exhaust system. The noise was a novelty at first but eventually it got on my nerves. I realize that many like that level of sound but it was not for me.

So in 2004 I dropped by the local Midas shop. They advised to retain the like-new chambered pipes back to where the pipe curves to the mufflers. They would then fab the short, curved pipes from the chambered sections to the mufflers. The theory being that chambered pipes are virually straightpipes and would flow pretty freely.

I agreed to this and they installed a couple of their turbo mufflers. They did a very nice job and the car was quieted down, perhaps too much quite frankly. But the car has run very nicely since and I did not give it much further thought.

But I have from time-to-time read of the restrictive nature of chambered systems and that did me pause for thought recently. If the back pressure in the chambered pipes is added to that in the turbo mufflers it might just be a bit too much. It doesn't seem to hamper runnability but I would imagine a freer-flowing system would be kinder to the engine. Any thoughts on this?

My instinct is to go back to basics and get an aftermarket, OEM-style complete 2" package for the 327/300 with Powerglide.

 

[Lucy64]

I have the under the car chambered pipes also. I ran them last year and you are correct about the noise. I don't mind it (in fact sort of enjoy the attention it draws) but my wife asked that I install something to tone it down some. I was thinking about doing exactly what you did by installing some Flowmasters in the back and leaving the chambered pipes. My concern was that it would be too quiet. I didn't think the backpressure thing would be a problem because they are pretty much straight thru anyways. I am very interested in what others think also.

 

[66 big block]

I have the under the car chambered pipes also. I ran them last year and you are correct about the noise. I don't mind it (in fact sort of enjoy the attention it draws) but my wife asked that I install something to tone it down some. I was thinking about doing exactly what you did by installing some Flowmasters in the back and leaving the chambered pipes. My concern was that it would be too quiet. I didn't think the backpressure thing would be a problem because they are pretty much straight thru anyways. I am very interested in what others think also.

I had off road mufflers from allens ok but switched to magna flow sounds great without being annoying

 

[paul67]

In the absence of further opinions this evening I am thinking of the Corvette Cental 2 1/2" OEM-like system with Magnaflow mufflers. Any thoughts on those?

 

[paul67]

This Forum is sure quiet!

 

[JohnZ]

I have a Paragon aluminized 2-1/2" replacement system on my '67 327/300, and it's just as quiet as the original stock system; I'd prefer it a bit louder (like the original N-11 Off-Road option), but nobody makes a reproduction of that muffler that sounds like the original - they're all too quiet. I think aftermarket mufflers are the only answer, but the variety is bewildering, and you almost have to listen to an installation with each choice to decide which one sounds "right" to you. Mine will remain with the stock configuration, for originality reasons.

 

[paul67]

John,
Those are wise words. I will wait for the driving season and when I hear a sound that appeals to me I will ask the owner what system he/she had installed. Listening to soundclips on the computer really is not realistic. And I don't wish to take a $500+ gamble.

 

[Viet Nam Vett]

For what it's worth... From what I understand..stock Corvette side pipes are only 1 7/8 " ID . If the under car chambered exhaust are similar in design this to me would be added restriction with a set of external mufflers. You might be better off with just a nice set of fresh bent 2 1/2 " pipes back to your muffler of choice.

I would think this would be much better then using Chambered pipes with Mufflers. Just my $.02 Worth..

 

[paul67]

The front pipes are indeed about 2". That expands to 2 1/2" in the chambered sections and carries back to the 2 1/2" inlets on the mufflers. The exhaust tips are the standard 2".

Another option might be to retain the chambered pipes and install the 2 1/2" Corvette Central Magnaflow mufflers. They are a straight-through design and set up with pipes and brackets specifically for a C2. I presume with that design they would offer little backpressure and give the car a little more mellow character on the noise side.

 

[Kid_Again]

OK, I'll bite.

If I understand your post correctly, you have a 300hp engine and the drivability is fine. Why mess with this unless the sound (or lack thereof, actually) drives you nuts. I would think that, with your current setup and you don't run the crap out of that engine, you should be OK, restriction-wise. I assume that you don't have headers.

Frankly, I'm on the other side of the equation. My wife just doesn't ride in my cars and I LOVE to listen to the engine so I went with the LOUDEST freakin' pipes I could. Still, I THINK I could have gone with the 4" chambers (they would JUST fit under the stock sp covers) but the very knowledgeable guy at Sweet Thunder talked me out of it.

 

[Lucy64]

Kid,

I think what he is saying is that he now has the chambered system and wants to add stock type mufflers also, leaving the chambered system in place. So he will have chambered AND mufflers. He is concerned that it will be a problem with both in place at the same time. I have the chambered system from Mid America and they are very loud. I don't mid it, in fact I enjoy it, but my wife is complaining. I may have to replace it with a pair of Flowmasters.

 

[paul67]

Yes, it is a 327/300 with Powerglide and driven as a passenger car on Sunday afternoon drives with the Wife. There is no attempt to gain performance here. Just a more mellow rather than silent exhaust note.

 

[GTR1999]

Paul,
I've run stock 2", stock 2.5", Hooker side pipes, Headers into stock exhaust, headers into 2.5 into 40 series Flowmasters, and chambered exhaust.

I got sick of the hooker pipes and afraid a kid would burn their hands on them.

The stock 2 or 2.5 were mellow and I kind of like that now.

The 40's are on my son's 400 hp 75 and I don't drive it anymore. After 30 years the appeal is waning for me I guess.

The chambered were the worse fitting,sounding piece of junk pipes of the lot.
Of course this is just my opinion on the matter.

The system I'm going to use on my 72 this Spring is headers into 2.5" and 50 series Flowmasters.

 

[75 flame orange]

magnaflow system

In the absence of further opinions this evening I am thinking of the Corvette Cental 2 1/2" OEM-like system with Magnaflow mufflers. Any thoughts on those?

paul
i put the corvette central's 2 1/2" system with magnaflow's on my 75 last spring.they sound and performe great,i would highly recomend them.
carmen

 

[ZRGator]

I didn't see it mentioned, but do you have the 2" exhaust manifolds or the
2 ½" manifolds?

 

[paul67]

I have 2" exhaust manifolds but the front pipes expand to 2 1/2" at the chambered pipes.

Carmen,
I know this is so, so subjective but could you give me reading on the noise level. Much like late-model Mustang? Wakes up the entire neighbourhood at midnight? Can be heard from three miles away at 3:00am? Police warm-up their pencils when you drive by? Sets off car alarms in underground parking?

 

[paul67]

I will speak with my Midas specialist tomorrow re the Magnaflows. He did the original install of the Midas turbos. An old car person. No axe to grind. Spent 20 minutes centering the exhaust tips through the bezels to my satisfaction. You have to love competent and caring people.

 

[75 flame orange]

60's--70's

I have 2" exhaust manifolds but the front pipes expand to 2 1/2" at the chambered pipes.

Carmen,
I know this is so, so subjective but could you give me reading on the noise level. Much like late-model Mustang? Wakes up the entire neighbourhood at midnight? Can be heard from three miles away at 3:00am? Police warm-up their pencils when you drive by? Sets off car alarms in underground parking?

paul
the sound is a throaty sound, like the muscle car's of the late 60's earley 70's
i have no cat. no y pipe, just straight 2 1/2 pipes and mufflers,like a 74 vett system.just standing behind the car while it's idling is like music to your ears!!!
carmen

 

[paul67]

Carmen,
Thanks for that message. I may just go with the Magnaflow.

 

[paul67]

Just to close this out I will stay with the current system that works well and is new. I cannot justify new $s in my own mind for a little bit more noise. Thanks for listening and I do apologize for my musings.