What is the factory size exhaust for a 1970 454? [Archive] - Chevelle Tech

: What is the factory size exhaust for a 1970 454?


weister1
Nov 30th, 99, 2:35 AM
I'm about to purchase a stainless steel exhaust system for my car and I want to get the 'correct' size. Also, anybody no of any drawbacks to putting in the stainless?
Thanks,
Dave

TK-70
Nov 30th, 99, 9:53 AM
For what it's worth, my '72 SS454 used 2-1/2" exhaust. Key point is that the big block tailpipe end runs parallel to the ground and terminates under the rear bumper with the expectation of a chrome exhaust tip being attached. The small block exhaust typically does a 45 degree downturn at the rear bumper with no chrome tip. Don't get the angled tailpipe if you plan to use chrome exhaust tips.
I haven't used stainless steel, so I can't comment. Hope this helps. TK

weister1
Nov 30th, 99, 3:09 PM
Thanks for the reply, I am going to use the factory SS tips (I have an NOS set), I'm concerned if the stainless steel will be too hard to modify if it should be the wrong size to accomodate the tips-I was thinking 2 1/2" was it I'm still hoping for a little affirmation though from some others!
Thanks,
Dave

Alan F
Nov 30th, 99, 3:53 PM
Dave,
The 'correct' size (as it pertains to oem) exhaust is 2.5" headpipes and 2.25" tailpipes. It would be helpful to know why you are concerned with the 'correct' size (originality or performance). If you're talking about a concours, why go stainless? There's no downside to stainless - most consider it an upgrade. Are you buying someone's kit, ie. Borla, etc.? It'll probably have 2.5" tailpipes. Or, have you found someone to mandrel bend the stainless pipe? Either way, should be the last system that car ever needs.

JSL
Nov 30th, 99, 5:48 PM
Take a look at the Ground up catalog, they have some nice original style exhaust systems there, even the chambered system


Jeff

SSteve L
Nov 30th, 99, 6:25 PM
I have a set of the NOS tips and the 2.5" pipe of my flowmaster system fits perfectly inside of them. Does anyone know how far the flat area on the top of the exhaust tip is supposed to be below the bottom of the valence panel?? The way mine sits right now, they look a little low, and before I weld them on I was thinking of bending the tailpipes uppward a bit.



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Steve

72 Chevelle SS402/4sp

weister1
Nov 30th, 99, 6:59 PM
Alan, I'm doing this for a frame off restoration-maybe not a 'concourse' restoration, but a resto that I can drive and will look good and last over the years. So the stainless is for longevity and quality, not so much as performance. But I do still want the NOS tips to fit; also another question posted was a good one where and how do you line up the tips? What are the markers to find the correct are?
Thanks again,
Dave

Narti
Nov 30th, 99, 7:20 PM
Hey Weister,
Go to www.gardnerexhaust.com (http://www.gardnerexhaust.com) . He make's exact copies of Chevelle or any other Muscle Car exhaust system's.
He should be able to answer all your question's. Narti.

------------------
Nick P.
Team Chevelle Gold #36
www.chevelles.com/showroom/Nick's1970ChevelleSS396.jpg (http://www.chevelles.com/showroom/Nick's1970ChevelleSS396.jpg)



[This message has been edited by Narti (edited 11-30-99).]

Dave Birdwell
Nov 30th, 99, 7:51 PM
The correct dimention for the extension is 7/8" down from the bottom of the valance panel, and they extend out 2 7/16" measured at the center of the tip to the bottom edge of the valance panel, measured parallel to the edges of the extension.

weister1
Dec 1st, 99, 3:14 AM
Thanks for the dimensions, and also thanks for the info on Gardner; I'll give them a call and see what they offer!
Dave

Cam
Dec 1st, 99, 3:44 AM
Aren't the '70 Chevelle SS's supposed to utilize resonators ahead of the exhaust tips? That is an item usually missed. Since you're looking for the stock appearance you should consider it.
BTW, please comment, anyone who knows for sure on the resonators.

weister1
Dec 1st, 99, 4:26 AM
As far as I know resonators were not used on SS's (big blocks)
Dave

Alan F
Dec 1st, 99, 6:38 AM
Dave,
Resonators are used on the '70 SS. Gardner includes them in their package. Also, I believe that the stock tips can be expanded to fit on a 2.5" pipe.
Alan

Havoc
Dec 1st, 99, 2:09 PM
How does the Gardner exhaust sound? Has anyone heard one? Do they have their own mufflers, or can you just use a set of Flowmasters or whatever? Thanks.

------------------
Ian McDermott
1970 Chevelle SS 396
Gold Member #101
E-mail: havoc@chevelles.com
Web page: chevelle.dhs.org (http://chevelle.dhs.org)
ICQ UIN: 3923441

Narti
Dec 1st, 99, 6:38 PM
I've got a Gardner exhaust system on my car, not as loud as Flowmaster's or Dynomax, just a nice Big Block RUMBLE http://www.chevelles.com/forum/smile.gif
BTW, yes resonator's are supposed to be on the 70 big block car's, Gardner will make them either way for you.

------------------
Nick P.
Team Chevelle Gold #36
http://www.chevelles.com/showroom/Nick's1970ChevelleSS396.jpg

Rick Cell
Dec 1st, 99, 6:49 PM
Go to the Gardner web site and you can hear sounds from different exhaust systems they manufactered. I purchased a set of rear tailpipe hangers for my 70 and they looked great. They are good people to deal with and the contact person their is Eric Garner.