Through frame exhaust, how do I do it? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

INSIDIOUS '86 · 07-09-2012, 02:21 PM

So I need to run my 3" tailpipes through the frame right behind the front lead spring mounts. Can i just cut a hole or do i need to run a larger thick pipe through with it boxed?
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INSIDIOUS '86 · 07-12-2012, 01:44 PM

TTT

Nobody holed a frame here?
Moderators maybe this would be better moved to the suspension section if you would be so kind
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**RPOZ11** · 07-13-2012, 02:19 AM

I sorat got that idea from how Corvettes route their exhaust piping back.

I figure you need to determine where your head pipe starts, in relationship to the distance to the muffler.

When you decide that, then you can start measuring where the area you need to modify lies.

I thought that round steel piping with ".xxx" wall thickness is somewhat necessary to provide strength and hole sizing.

mcmlxix · 07-13-2012, 06:17 AM

If its close to the spring hanger, I would definitely box the frame and weld in a 3.5" to 4" pipe the same thickness as the frame. Then pass the exhaust through the new oversized pipe...

INSIDIOUS '86 · 07-13-2012, 05:28 PM

So if its boxed and the pipe is the same thickness as the frame its fine? Its going to be like a 3'1/4-1/2 hole and i beleive the frame is six inches tall at that section.

What would you guys do with brake lines? Also. Do i weld with vehicle weight in the wheels or any special supports?
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07-09-2012, 02:21 PM	#1
INSIDIOUS '86 Registered User Join Date: Jul 2009 Location: washington Posts: 4,178	Through frame exhaust, how do I do it? So I need to run my 3" tailpipes through the frame right behind the front lead spring mounts. Can i just cut a hole or do i need to run a larger thick pipe through with it boxed? Posted via Mobile Device __________________ 377 sbc thumpr cam autogear m23 muncie 3:73 Detroit trutrac 3''spintech prostreet mufflers xpipe 1 3/4 headers build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217 Iroc gauge threadhttp://67-72chevytrucks.com/vboard/s...d.php?t=554511

07-12-2012, 01:44 PM	#2
INSIDIOUS '86 Registered User Join Date: Jul 2009 Location: washington Posts: 4,178	Re: Through frame exhaust, how do I do it? TTT Nobody holed a frame here? Moderators maybe this would be better moved to the suspension section if you would be so kind Posted via Mobile Device __________________ 377 sbc thumpr cam autogear m23 muncie 3:73 Detroit trutrac 3''spintech prostreet mufflers xpipe 1 3/4 headers build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217 Iroc gauge threadhttp://67-72chevytrucks.com/vboard/s...d.php?t=554511

07-13-2012, 02:19 AM	#3
RPOZ11 72 BB C30 Super LongHorn Join Date: Nov 2002 Location: Chavez Ravine Posts: 1,606	Re: Through frame exhaust, how do I do it? I sorat got that idea from how Corvettes route their exhaust piping back. I figure you need to determine where your head pipe starts, in relationship to the distance to the muffler. When you decide that, then you can start measuring where the area you need to modify lies. I thought that round steel piping with ".xxx" wall thickness is somewhat necessary to provide strength and hole sizing. __________________ 72 BB C/30 Longhorn Super HO72 No-Spin, #'s matching, Tilt, Tach, AC, AM/FM HO72 build : http://67-72chevytrucks.com/vboard/s...d.php?t=714492 2017 SS

07-13-2012, 06:17 AM	#4
mcmlxix Collector of Projects Join Date: Apr 2003 Location: Las Vegas Posts: 3,106	Re: Through frame exhaust, how do I do it? If its close to the spring hanger, I would definitely box the frame and weld in a 3.5" to 4" pipe the same thickness as the frame. Then pass the exhaust through the new oversized pipe... __________________ Rich 1972 K5 Blazer CST Click HERE D60 BIG BRAKE UPGRADE Click HERE

07-13-2012, 05:28 PM	#5
INSIDIOUS '86 Registered User Join Date: Jul 2009 Location: washington Posts: 4,178	Re: Through frame exhaust, how do I do it? So if its boxed and the pipe is the same thickness as the frame its fine? Its going to be like a 3'1/4-1/2 hole and i beleive the frame is six inches tall at that section. What would you guys do with brake lines? Also. Do i weld with vehicle weight in the wheels or any special supports? Posted via Mobile Device __________________ 377 sbc thumpr cam autogear m23 muncie 3:73 Detroit trutrac 3''spintech prostreet mufflers xpipe 1 3/4 headers build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217 Iroc gauge threadhttp://67-72chevytrucks.com/vboard/s...d.php?t=554511



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