I would like to have the benfit of the members here in making a decision on what exhaust system to get for my 67 RS convertible. I have read quite a bit about good choices for Coupes, but they usually come with the disclaimer that they won't fit the convertible.

As for the exhaust note, I do not want to have a very loud system, something of a mellow rumble, not a roar. (I like the Z06 Corvette sound) After all, this is a convertible, not a drag car.

My engine is a 327 with 9.7:1 compression, Edelbrock Performer RPM Heads and Intake, Comp XE242 cam, Holley 670 Avenger Carb. Hooker Competition Headers.

Any suggestions? Thanks very much

My vote is for the Flowmaster system. The sound is perfect for me but may not be for others.
You can go to the Flowmaster site and see a video with sound if interested.

Are you going to put headers on?

The system will fit but you may have to have someone install it that is willing to do it the correct way. You could also have a shop make you a custom system.

I have a 69 so am not 100% sure of the 67 fit.

Go with Magnaflows and have a muffler shop do a 2 1/2" pipe from the collector to the muffler and a 2" or 2 1/4" from the muffler to the back of the car. I have them on my ragtop and it's quite until you put your foot into it... The wife and daughter didn't even hear me pull in after making a test run around the neighborhood yesterday but they heard me leave when I was around the corner...

I have 3" in/2.5" out Dr. Gas X-pipe going into 2.5" Magnaflows. I was able to fit it pretty tight to the floor. It sounds quite nice and civil cruising but 'nicer' when I step on it. This is connected to 1 5/8" headers.

Originally posted by DjD:
Go with Magnaflows and have a muffler shop do a 2 1/2" pipe from the collector to the muffler and a 2" or 2 1/4" from the muffler to the back of the car. I have them on my ragtop and it's quite until you put your foot into it... The wife and daughter didn't even hear me pull in after making a test run around the neighborhood yesterday but they heard me leave when I was around the corner... I have the Magnaflows as well. They have a great rumble with the big block and are not real loud until you want it to be. 2-1/2" tubing as well. You will be hard pressed to get anything larger in your vert.

RickD,

How on earth did you fit 3" pipe AND an Xpipe on a convert? Do you still have the X-brace in the car? I'd love to see some pictures if it's not too much of a bother.

-Al

I'll take a few pics. Yes, I have the cross brace ( not the bolt-on x-brace). The 3" goes from the header collector to the 'X', then 2.5" on back. I had Dr. Gas bend the rear legs out of the X a little tighter so I could get it better up into the tranny tunnel. I will say, the tranny crossmember is about a fat 1/8" from the pipe. I put some thermo-shield reflective stuff there and have had no problems. I'll shoot some pics but don't have a way to post. I can email them to you or someone who might be able to put up for all to see.

I tried to post the pic, but not having any luck, so here is a link to RickD's X-pipe exhaust system. Very sanitary.

Bad Link - I'm a dork. Please see below.

I apologize for not reading you prior post carefully enough, Rick. I was thinking you were able to stuff all of this up under the removeable X-brace. Which brings me to my next question - how did the removal of that brace affect the handling and rigidity of your car? Do the weld in subframe connectors make it unnecessary?

Thanks!

-Al

[ 07-16-2003, 05:24 PM: Message edited by: BPOS ]

BPOS, that link does not work from here.
I'm also interested in seeing it :cool:

http://community.webshots.com/photo/74560744/81558946uyVeaJ

Oops. I'm an illiterate when it comes to computers. Hope this works!! Let me know.

Here are some photos of my setup. 3" to homemade X-crossover with 2.5" out to mufflers and 2.25" after mufflers.

http://www.geocities.com/hrayhouston/exhaust.html

The X-crossover angles up slightly to fit in the trans tunnel. I made this setup myself with the car on jackstands. All bends are made from sections cut from a prebent tight radius "donut".

This would have been easier with a stock tranny, but my crossmember is moved back for the 700r4 in the photo, and now for my Tremec.

Nice work you guys, thanks!
;)

BPOS, unless your running a Roll Cage...the X-brace is important as it helps tie both sides of the car together. Shim it if you have to and use high grade bolts/spacers but i would not leave the brace off, especially if your making some serious HP/Torque.

I thought of pulling mine off as well to fit a 3 inch exhaust syestem but decided on a 2.5 inch mandrel bent exhaust system and used 1/2 inch spacers to lower the brace a notch. Fits nicely now. I'm Glad I left the brace on.

BTW, I've seen some use stacks of washers as spacers for the x-brace but I personally wouldn't recommend that route. graemlins/clonk.gif

Good Luck!

-Chris

I have welded SFC's, solid body mounts and the car feels ok. My doors close perfectly but I don't do 'Dukes of Hazzard' jumps. In a few weeks a local fabricator is putting in an 8 pt. rollbar. Clearly, this will help. I agree the bolt-in x-brace is a benefit. Lacking it hasn't significantly affected my car. I considered spacing it down but it would become my lowest point and I knew I would be adding some type of rollbar.

Bill,

I have a 69 drop top. I used to have Magna Flows with 2.25 inch pipe and liked the sound but have recently changed to the Flowmaster American Thunder system with 2.5 inch pipe and like it much better. It was a little loud right after installation but mellowed over the next 500 to 1000 miles. It now sounds like a muscle car. It is pretty mellow at idle but roars at WOT. I have heard that some have had trouble getting it to fit under the X-brace but mine fit with just a little shimming of the X-brace. Here is a pic of the X-brace.

http://homepage.mac.com/bspears/.Pictures/Photo%20Album%20Pictures/2003-01-14%2016.11.30%20-0800/ImageDSCF0194.jpg

I have a lot more pics of the build up. Just click on the link in my sig if you are interested.

good luck with your project

bob spears

Bob,

Are you running an American Thunder (FM kit 17139) or a Force II (FM kit 17104) exhaust system? I looked at the pics on your website and it looks like you have the transverse muffler. When I look at the Flowmaster website the kit for the American Thunder has two series 40 mufflers vs. the Force II kit has the transverse muffler.

Thanks,

Ted

Thanks for the great information here. Looks like there are quite a few answers here. (great photo too!) I will most likely find an exhaust installer with some of the info here to narrow down the search.

Originally posted by rpol78:
Bob,

Are you running an American Thunder (FM kit 17139) or a Force II (FM kit 17104) exhaust system? I looked at the pics on your website and it looks like you have the transverse muffler. When I look at the Flowmaster website the kit for the American Thunder has two series 40 mufflers vs. the Force II kit has the transverse muffler.

Thanks,

Ted Ted,

I thought it was the Flowmaster American Thunder system that was supposed to look like the stock SS dual exhaust system. I will do a little checking and get back to you with an exact answer.

bob

Bob,

This is the pic I was looking at. I'm looking for an exhaust system for my BB conv and most seem to view the American Thunder as too loud. Since Flowmaster advertises the Force II as quieter I was considering it but didn't know if I could get it to fit a conv. After looking at your headers I believe I can run these behind stock exhaust logs and get a similar fit. Does yours have stainless steel tail pipes? I didn't think the Force II system did.
http://homepage.mac.com/bspears/.cv/bspears/Sites/.Pictures/Photo%20Album%20Pictures/2003-04-08%2010.30.30%20-0700/Image-546C132269E711D7.jpg-thumb_140_105.jpg

Thanks,

Ted

Better Pic
http://homepage.mac.com/bspears/.Pictures/Photo%20Album%20Pictures/2003-04-08%2010.30.30%20-0700/Image-546C132269E711D7.jpg

Ted,

I just talked to the guy at Speed Merchant who ordered my exhaust system. I have the American Thunder System with the crossflow muffler. Part number is 17104. The pipe is aluminized steel. It is not stainless. I asked him about fitment to a stock exhaust manifold and he said it does come with the parts to do that but it will required some work to get it to fit. Good luck with your project.

bob spears

Bob Spears,
I am considering that same exhaust for my 69 coupe. I notice some catalogs list it as a
Force II but Flowmaster doesn't have a Force II system for the 69 Camaro, as you stated it is the American Thunder. How does your system sound inside the car while cruising at different speeds?
Is there a lot of interior "drone"?
Thanks, Guy

Guy,

Actually flowmaster on their website shows both systems in their "application guide" as american thunder but in their "kit diagrams" section they call kit 17104 with the transverse muffler the force II. The diagrams below are on flowmasters website. Maybe their inconsistency is confusing us.
http://www.flowmastermufflers.com/web10/openrd/attachment.php?s=&postid=333

http://www.flowmastermufflers.com/web10/openrd/attachment.php?s=&postid=305

Personally I'm thinking about using the american thunder kit, hooking it up to stock exhaust logs via mandrel bent pipes, and putting dynomax mufflers in place of the series 40 mufflers flowmaster provides. It looks like the dynomax mufflers outflow the flow masters and are quieter. Also the american thunder kit uses the stock mount points and have the stainless steel tips. If my thinking is correct I can have my cake and eat it too. smile.gif I have a big block Z11 and don't want to drill extra holes in it since at some point I'd like to restore it. Also from some of the messages posted it sounds like the force II tail pipes show below the quarters more. Has anyone out there seen both systems? If so which one looks more original when looking at the topside of the car? Anyone out there with a similar setup to what I described?

Thanks Ted

Ted, your right, they do show it as the F II. Were you going to buy the complete system and ditch the mufflers or can you buy the "kit" without the mufflers?
Guy

gjohnson,

I do not get any of the droning I have heard others say you can get with the Flowmasters. It has a very nice idle. It really does scream at WOT though. I am very happy with the sound. I will include a link to my webpage, I have a vid of my first dyno run and you can take a listen. The sound has a funny quality on the vid due to compression artifact but you can get a feel for it.

VId of dyno run (http://homepage.mac.com/bspears/iMovieTheater18.html)

Here is another link of a canyon carving vid with some engine sounds at the beginning and end of the vid. Take a listen if you like.


canyon carving vid (http://homepage.mac.com/bspears/iMovieTheater28.html)

good luck with your project

bob spears

gjohnson,

To my knowledge I have to buy the whole kit. FM may sell the individual pipes but I'll bet it would cost more than summit or jegs sells the kit for. Maybe I can sell the 40 series mufflers on ebay or I'd have the option of trying them, but from the posts I've read I think they'll be too loud for my taste. I currently have a fairly new reproduction system with the transverse muffler on the car. I like the sound but it looks pretty restrictive with all of the bends and the places where they flattened the pipes for clearance. I'm getting ready to build an 396/375 configuration only with the aluminum L89 heads and a different cam. My goal is to have it look pretty original under the hood and topside of the car.

Ted