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#2427941 - 01/02/18 05:15 PM Exhaust size for 5.7
kpzbee Offline
super stock

Registered: 01/20/03
Posts: 877
Loc: Wooster, Ohio
I'm doing a Eagle swap into mt '73 AMC Javelin and am currently looking at how to route exhaust under it before I finish up my trans tunnel. I'm using OE SRT shorties and they measure 2.75" ID. Would 2.5" be adequate or should I go 3" back to the mufflers and 2.5 tailpipes? I'm going to have to use oval pipe since clearance is an issue. This is a street driver used for long hauls so wringing every bit of hp is not my main concern. Thoughts? Suggestions? Thanks.
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"It's funny how one project eventually leads (or forces) you into another one.
It's really just one endless project designed to induce insanity and bankruptcy."

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#2427960 - 01/02/18 06:00 PM Re: Exhaust size for 5.7 [Re: kpzbee]
sixpackgut Offline
Drag Week Mod Champion

Registered: 06/08/03
Posts: 9031
Loc: Charleston
Im a min 3" guy. I would put 3" on a lawnmower
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Gen 3 power 6.22@110, 9.85@135

performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs

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#2428010 - 01/02/18 07:21 PM Re: Exhaust size for 5.7 [Re: kpzbee]
GoodysGotaCuda Offline
5.7L Hemi, 6spd

Registered: 11/23/04
Posts: 24047
Loc: Texas
If you're staying with stock manifolds, I would leave it as 2.5".
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1972 Barracuda - 5.7L Hemi, T56 Magnum 6spd - Build page -> https://www.facebook.com/GoodysGotaHemi<-
1976 Dodge Warlock - "Her Truck" - 360/727 2wd
2016 BMW X1
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#2428024 - 01/02/18 07:48 PM Re: Exhaust size for 5.7 [Re: kpzbee]
aus370 Offline
member

Registered: 10/17/17
Posts: 14
Loc: Australia
I'd do the 3.0 to the muffs , then 2.5 after that , and put some straight through offset muffs in the tail pipes if you want it a little quieter .
And some sort of balance pipe is a must , but that's just my opinion .


Edited by aus370 (01/02/18 07:54 PM)

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#2428198 - 01/03/18 07:34 AM Re: Exhaust size for 5.7 [Re: kpzbee]
ric3xrt Offline
super stock

Registered: 01/13/06
Posts: 830
Loc: Sellersville Pa
My .02 is 2.5in with an X-pipe 2.5in tail pipe,
3in no X-pipe, 2.5 tail pipe

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#2428762 - 01/04/18 06:58 AM Re: Exhaust size for 5.7 [Re: kpzbee]
kpzbee Offline
super stock

Registered: 01/20/03
Posts: 877
Loc: Wooster, Ohio
Thanks for the opinions. I'm going to go with 2.5" X pipe system. Getting 2.5" tailpipes in there is going to be tuff but it will happen somehow.
_________________________
"It's funny how one project eventually leads (or forces) you into another one.
It's really just one endless project designed to induce insanity and bankruptcy."

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#2428994 - 01/04/18 02:46 PM Re: Exhaust size for 5.7 [Re: kpzbee]
WO23Coronet Offline
master

Registered: 01/08/08
Posts: 3905
Loc: Canada
How well do the SRT shorties fit?

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#2429368 - 01/05/18 07:06 AM Re: Exhaust size for 5.7 [Re: WO23Coronet]
kpzbee Offline
super stock

Registered: 01/20/03
Posts: 877
Loc: Wooster, Ohio
The right side fits perfect but the left is hitting the starter. The car version swings away from the block further so I have a pair of those on the way to see if that will work. I'm trying to avoid the cost of special headers. I'm having to use a 4L60E trans so there's an adapter in it and it makes the starter stick out slightly further than it did on the 518. frown I couldn't get the 518 to fit in the tunnel with the Hemi like it did with the Magnum I had in it.

I picked up a 3' length of 2.5" pipe yesterday and with some drive shaft tunnel "massaging" it will fit, abet very tight. A tight X pipe should fit right behind the X member.
_________________________
"It's funny how one project eventually leads (or forces) you into another one.
It's really just one endless project designed to induce insanity and bankruptcy."

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