Factory cross-member mod ??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Spray-Bomb · 03-10-2007, 01:28 AM

I plan to run 3" exhaust on my truck & was wondering how big of holes I can cut in my cross-member that holds the carrier, without making it weak

I was thinking a 4" hole for each pipe would be enough clearance, but would this weaken it so much that I would need to weld in some additional "support metal" to make it strong again?

Please, no comments like ( 3" is too big )

Also has anyone ran the CherryBomb Extreme mufflers ?

Thanks, Matt

RACINJASON22 · 03-10-2007, 01:35 AM

Never done it myself but it's in the plans. I've seen and plan on cutting the holes and then adding a short 1" or so piece of pipe to the outside of the hole welded in. There's people on here that have done it recently hopefully they will chime in with some help. Good luck with it. RJ22

cableguy0 · 03-10-2007, 01:44 AM

just use thick tubing around the hole to strengthen it back it up and it will be fine. cut the hole to the size of the tube and let it hang out an inch or so on each side.just weld it in to give the support back

RACINJASON22 · 03-10-2007, 01:48 AM

cableguy0 worded it better than me. I have a had time wording things but, that was what I was trying to say.

Spray-Bomb · 03-10-2007, 02:06 AM

Thanks guys

I was thinking I would need to brace it a little, I really like the thick-wall pipe idea

But why an inch, wouldn't a half or a quarter be good enough

IvelDesigns · 03-10-2007, 02:11 AM

here's a step by step guide from the FAQ. i'm starting this mod this weekend.

http://67-72chevytrucks.com/vboard/s...d.php?t=201474

Spray-Bomb · 03-10-2007, 02:19 AM

Thanks for the FAQ, but I still don't understand why you need so much extra pipe

cableguy0 · 03-10-2007, 02:23 AM

it stops the pipe from being able to collapse easily if you used a really short pipe it would be just the same as not using pipe at all

Spray-Bomb · 03-10-2007, 02:25 AM

Duh, I dunno why I didn't thin of that

I guess I'm getting tired

Thanks

70GMCer · 03-10-2007, 07:43 AM

3" is too big.......had to say it.........hehe

Joe67 · 03-10-2007, 08:35 AM

Quote:

Originally Posted by 70GMCer

3" is too big.......had to say it.........hehe

She's never told me that

Joe67 · 03-10-2007, 08:36 AM

This mod is on my to do list for sure

Quote:

Originally Posted by IvelDesigns

here's a step by step guide from the FAQ. i'm starting this mod this weekend.

http://67-72chevytrucks.com/vboard/s...d.php?t=201474

First time I've seen that FAQ page - thanks

Spray-Bomb · 03-10-2007, 11:23 AM

Quote:

Originally Posted by 70GMCer

3" is too big.......had to say it.........hehe

I was just waiting for somebody to say that

gene_ensor · 03-10-2007, 06:51 PM

I approve of the oversized pipe welded in, however I would rather have the exhaust firmly attached to the frame to minimize vibrations etc.

Does anyone know where you can get the exhaust clamps Stacey used on Copperhead? Does anyone have pictures of a half-breed clamp with the pipe welded into the cross member?

Spray-Bomb · 03-10-2007, 10:11 PM

What kind of pics do you want ???

Yeah if somebody could post up some pics of different exhaust hangers that'd be cool

Also, do I really need 1/4" pipe when the cross-member isn't that thick ?

Man I can't wait until Stacey is back on the "air"

03-10-2007, 01:28 AM	#1
Spray-Bomb Texas Big Wig Join Date: Jan 2007 Location: Mineola, Texas Posts: 5,620	Factory cross-member mod ??? I plan to run 3" exhaust on my truck & was wondering how big of holes I can cut in my cross-member that holds the carrier, without making it weak I was thinking a 4" hole for each pipe would be enough clearance, but would this weaken it so much that I would need to weld in some additional "support metal" to make it strong again? Please, no comments like ( 3" is too big ) Also has anyone ran the CherryBomb Extreme mufflers ? Thanks, Matt __________________ Just not low enough... ----------------------------- Sinister Killer

03-10-2007, 01:35 AM	#2
RACINJASON22 GEARHEAD Join Date: Jan 2007 Location: CENTRAL,PA Posts: 2,284	Re: Factory cross-member mod ??? Never done it myself but it's in the plans. I've seen and plan on cutting the holes and then adding a short 1" or so piece of pipe to the outside of the hole welded in. There's people on here that have done it recently hopefully they will chime in with some help. Good luck with it. RJ22 __________________ 72 SWB 2WD MY PROJECT 72 LWB 4X4 FUTURE PROJECT SUBSCRIBE HEREBOARD VENDORS HERE NORWOOD MEET SURVIVOR!

03-10-2007, 01:44 AM	#3
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,948	Re: Factory cross-member mod ??? just use thick tubing around the hole to strengthen it back it up and it will be fine. cut the hole to the size of the tube and let it hang out an inch or so on each side.just weld it in to give the support back __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

03-10-2007, 01:48 AM	#4
RACINJASON22 GEARHEAD Join Date: Jan 2007 Location: CENTRAL,PA Posts: 2,284	Re: Factory cross-member mod ??? cableguy0 worded it better than me. I have a had time wording things but, that was what I was trying to say. __________________ 72 SWB 2WD MY PROJECT 72 LWB 4X4 FUTURE PROJECT SUBSCRIBE HEREBOARD VENDORS HERE NORWOOD MEET SURVIVOR!

03-10-2007, 02:06 AM	#5
Spray-Bomb Texas Big Wig Join Date: Jan 2007 Location: Mineola, Texas Posts: 5,620	Re: Factory cross-member mod ??? Thanks guys I was thinking I would need to brace it a little, I really like the thick-wall pipe idea But why an inch, wouldn't a half or a quarter be good enough __________________ Just not low enough... ----------------------------- Sinister Killer Last edited by Spray-Bomb; 03-10-2007 at 02:07 AM.

03-10-2007, 02:11 AM	#6
IvelDesigns Commander Taco Bello Join Date: Sep 2006 Location: Des Moines, Iowa Posts: 2,232	Re: Factory cross-member mod ??? here's a step by step guide from the FAQ. i'm starting this mod this weekend. http://67-72chevytrucks.com/vboard/s...d.php?t=201474 __________________ Bagged '50 3600 - Bumper punchin' road kill since 2009... Bagged '69 C10 Longbed - Bumper punchin' road kill since 2007...

03-10-2007, 02:19 AM	#7
Spray-Bomb Texas Big Wig Join Date: Jan 2007 Location: Mineola, Texas Posts: 5,620	Re: Factory cross-member mod ??? Thanks for the FAQ, but I still don't understand why you need so much extra pipe __________________ Just not low enough... ----------------------------- Sinister Killer

03-10-2007, 02:23 AM	#8
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,948	Re: Factory cross-member mod ??? it stops the pipe from being able to collapse easily if you used a really short pipe it would be just the same as not using pipe at all __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

03-10-2007, 02:25 AM	#9
Spray-Bomb Texas Big Wig Join Date: Jan 2007 Location: Mineola, Texas Posts: 5,620	Re: Factory cross-member mod ??? Duh, I dunno why I didn't thin of that I guess I'm getting tired Thanks __________________ Just not low enough... ----------------------------- Sinister Killer

03-10-2007, 07:43 AM	#10
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	Re: Factory cross-member mod ??? 3" is too big.......had to say it.........hehe __________________ 1997 GMC Sierra Ext 1965 Mustang

03-10-2007, 06:51 PM	#14
gene_ensor Registered User Join Date: Oct 2005 Location: Rapid City South Dakota Posts: 39	Re: Factory cross-member mod ??? I approve of the oversized pipe welded in, however I would rather have the exhaust firmly attached to the frame to minimize vibrations etc. Does anyone know where you can get the exhaust clamps Stacey used on Copperhead? Does anyone have pictures of a half-breed clamp with the pipe welded into the cross member? Attached Images

03-10-2007, 10:11 PM	#15
Spray-Bomb Texas Big Wig Join Date: Jan 2007 Location: Mineola, Texas Posts: 5,620	Re: Factory cross-member mod ??? What kind of pics do you want ??? Yeah if somebody could post up some pics of different exhaust hangers that'd be cool Also, do I really need 1/4" pipe when the cross-member isn't that thick ? Man I can't wait until Stacey is back on the "air" __________________ Just not low enough... ----------------------------- Sinister Killer



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