Hello, I'm restoring my 67 chevelle convertible. I need some advice on what is a really good exhaust system. I noticed NPD offers a 2 1/2" setup with Flowmasters. Summit offers a 3" setup with Flowmasters. Any advice on what is a good one. I have a 396 going in the car. Is the 3" worth the extra money?

I wouldn't go 3" unless you're going to be running 450+ hp. If you do go 3", I like the Torque Tech system.

I am going flowmaster system on mine also. After talking to a lot of people, I am going 3 in to the mufflers and 2 1/2 after. The exhaust gas will be cooled enough after the mufflers to keep the added horsepower of the 3 inch but a little quieter. MHO Something to think about.
Herbie

i have the 3inch flowmaster on my 66 and love it!!.. sounds great and turns alot of heads.. not too loud in the car either...Sean

For a 396,stick with the Flowmaster 2.5" system

I have a 71 with a complete 3 inch flowmaster system with the 40 series flowmaster mufflers. I had a 2.5 inch before and it was too quite. I have had a lot of heads turn and dont regret going with the 3 inch system. My engine is a 350ci and sounds more like a BB with the system i have on mine.

Personally I prefer the 3 inch over the 2.5. If you are going to go 2.5 I would go with a stock setup instead of the 3 inch because the sound difference is negligable between stock and 2.5. If your going to spend the money on the 2.5 you may as well spend the extra 100 bucks and get the 3 inch system.

You wont regret it!

I have the Flowmaster 3" on my 66 with Super 40 mufflers and love it. The car has a 355 sbc 11:1 comp .562 lift cam, and it sounds just like friends of mine that have big blocks. I wish I could post pics and sound clips on here, so that you could listen to it and check out the custom work I did with Stainless steel to run it straight out the back. The 3" Flowmaster kit has the turn down right behind the rear tire. I didn't like that, so I cut some of the bends and turned it so that it runs straight out the back. 3" all the way. There's nothing that looks better than big sewer pipe sticking out the back.

Is your intent to make the sound the way you want it or for better performance? I think if it is for performance on a street driven vehicle do not bother. If it is for sound then consider it.

Here's my pics. www.putfile.com/chevydog66

hey chevydogg66, I love the video, awesome sound. Man it's a hard decision. Being a convertible I mainly want it for the sound. The motor is a 396 and on a dyno was pushing 540 hp. I appreciate the input, anymore suggestions would be appreciated, thanks again, Clyde

My son put three inch all the way on his 540 600horse with flowmasters, and it sounds, how do I put it, cannonish, it's didn't have that desired tin can sound that a good set of flowmasters should have.

It's hard to describe the sound, but it wasn't as good with the three inch.

Rob

hey chevydogg66, I love the video, awesome sound. Man it's a hard decision. Being a convertible I mainly want it for the sound. The motor is a 396 and on a dyno was pushing 540 hp. I appreciate the input, anymore suggestions would be appreciated, thanks again, Clyde

What the hell do you have on that.....a blower?!?!?!?!?!?!?

Was it a rolling dyno or a stationary motor dyno?

it was a staitonary dyno. I'm actually looking for a hardtop to play around with and drop that motor in. I'm really serious considering dropping a 502 crate EFI in my convertible. Man I have a ton of money and work in this thing.
I'm just still undecided which exhaust system to go with.

If you have a ton of time and money like I also do in my car, I wouldn't hesitate to go 3". Why skimp now?

If you do decide to go 3", I can tell you that installing the tail pipes is an exercise in patients.. There's not much room to work with..

I did the Summit 3" kit and had to do quite a bit of cutting & welding to make everything sit where it needed to..

Here's a couple of threads I had going when I did mine.. The second one has some pics of the results.. Good luck with your project..

http://www.chevelles.com/forums/showthread.php?t=130803

http://www.chevelles.com/forums/showthread.php?t=134712

For a 396,stick with the Flowmaster 2.5" system
:thumbsup: :thumbsup: :thumbsup: :thumbsup:

I did change my trans. crossmember when I went with the Flowmaster 3" kit. I purchased a new one from www.crossmembers.com in order to fit the 3" thru. My Hooker Super Comp headers didn't line up with the rise in the crossmember in order for the collector and 3" pipe to fit thru. I did have to tweak the passengers side 3" pipe a little in order for it to fit thru the new crossmember. But other than that it fit perfectly.

Well, I've decided to go with the 3" kit from Summit. I appreciate as always everyone's input.

Here's 2 sound clips of my 3" H-pipe exhaust system. One with Flowmaster super 40's and the other with Pypes violators....


Flowmasters.... http://media.putfile.com/Chevelle-exhaust-2


Violators.... http://media.putfile.com/Chevelle-with-Violator-mufflers