Cutting holes in crossmember for exhaust. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

DevinM · 07-28-2005, 09:17 PM

My truck is a "weekend driver" that only gets out when it's nice and sunny, and I drive less than 1000 miles a year. I don't race it, I just enjoy it.
Now, that being said....I just purchased a set of 3/4 headers from ECE and want to cut holes in my existing crossmember to run the exhaust through. My truck is dropped 4/6 and my current long headers are too low and banged-up.
Will I be OK? Should I re-enforce it? How would someone re-enforce it?

Sweet72 · 07-28-2005, 10:41 PM

Project CopperHead on Trucks TV had a cross-member that was cut and reinforced for the dual exhaust. I'm not sure what was used but it looked like a 1-2" section of 4-5" dia. pipe was welded into the holes to strengthen it. I think ECE offers a cross-member designed for lowered trucks.

DevinM · 07-28-2005, 11:05 PM

Sweet72, I spoke with the guys over at ECE. I advised that I was tight (very tight) on money, and could only afford the headers. They told me that since my truck is not a "daily driver", I could cut holes in my existing crossmember and not have any issues.

*Tanker350* · 07-28-2005, 11:15 PM

What about this?

68LSS1 · 07-29-2005, 03:49 AM

It probably would be OK as you state it's not a daily driver and you don't race it. But I don't think I'd ever feel comfortable without reinforcing the crossmember. Whether it be boxing it (which would be real easy but overkill) or just welding some plate over the hole and larger than what the hole will become. I've got the ECE crossmember pictured above and will be modifying it also as I don't trust it to stay together with what I plan on subjecting it to.

matthufham · 07-29-2005, 10:21 AM

brothers and ece makes a kit, but they're for lowered rides. if you're at stock stance the crossmember's hole for the drive shaft would be too high.

Tx Firefighter · 07-29-2005, 11:11 AM

Quote:

Originally Posted by matthufham

brothers and ece makes a kit, but they're for lowered rides. if you're at stock stance the crossmember's hole for the drive shaft would be too high.

He said he's lowered 4/6 in the first post, but he doesn't have the cash to buy an aftermarket crossmember.

I've cut a bunch of the stock ones and never reinforced the crossmember, without problems.

FirstGen · 07-29-2005, 11:19 AM

mine is just a stock cut one and 600 rwhp later... no problem.

matthufham · 07-29-2005, 12:21 PM

Quote:

Originally Posted by Tx Firefighter

He said he's lowered 4/6 in the first post

the poster above me didn't say if his truck was lowered

CHEVYE · 07-29-2005, 12:55 PM

FirstGen's truck is definetely lowered. it's an awesome truck too with a ton of power.

68LSS1 · 07-29-2005, 01:03 PM

Quote:

Originally Posted by matthufham

the poster above me didn't say if his truck was lowered

If you are referring to me, info in my sig. Fatman Fab on front w/coilovers and HTH kit in the back. Will have around 550rwhp N/A and around 800rwhp with some nitrous assist. And the crossmember that Brothers sells is ECE's. Ask me how I know.

Low69CST · 07-29-2005, 01:34 PM

Didn't 3/4 tons come braced fromt he factory? You could find a pair of those out of a junk yard. You could also make and weld in some metal to box in the crossmemeber. Also, I think you'll have to mount the exhaust solid to the frame. That means you'll have to install flex joints like they did on Trucks. I'm not sure what they cost.

matthufham · 07-29-2005, 01:45 PM

Quote:

Originally Posted by 68LSS1

Ask me how I know.

ok, how do you know? because they look exactly alike and the pictures are very similar?

also you got a nice little truck started there i saw the pics.

Joe67 · 07-29-2005, 04:50 PM

Quote:

Originally Posted by Sweet72

Project CopperHead on Trucks TV had a cross-member that was cut and reinforced for the dual exhaust. I'm not sure what was used but it looked like a 1-2" section of 4-5" dia. pipe was welded into the holes to strengthen it. I think ECE offers a cross-member designed for lowered trucks.

I thought Copperhead was running the custom cross member from ECE

matthufham · 07-29-2005, 05:10 PM

it probably did since ece basically provided everything for that truck.

68Stepbed · 07-29-2005, 11:33 PM

Copperhead isn't running the ECE crossmember. They advertised it on TRUCKS! TV after Copperhead was finished. It has a modified stock piece.

I had a friend modify his. He cut holes big enough for 3" pipe. Slid a piece of 3" pipe about 3-4" long and welded em in. He was only gonna use 2 1/4" pipe for his exhaust so he had plenty of clearance. I'm gonna do the same but I'll use bigger pipe so I can run 2 1/2" exhaust.

Welding a piece of pipe in actually strengthens the crossmember. Probably better than it was to begin with IMO.

*newin72* · 07-30-2005, 12:47 AM

ok, I have every copperhead episode on the DVR, I will have to settle this!

give me a little bit to go through them all and find it...

*newin72* · 07-30-2005, 12:53 AM

68stepbed is correct! man that's an awesome truck!

68LSS1 · 07-30-2005, 03:01 AM

Quote:

Originally Posted by matthufham

ok, how do you know? because they look exactly alike and the pictures are very similar?

also you got a nice little truck started there i saw the pics.

lol, because I got the one from Brothers and it has Early Classics logo stamped in the bottom of the crossmember. I will post some pictures in a few weeks of the modifications.

ACES · 07-30-2005, 05:38 AM

My truck has holes cut in the crossmemeber and its just fine. I do want to note, that I don't have much horsepower either.

Here is a bad picture of it:

matthufham · 07-30-2005, 10:18 AM

Quote:

Originally Posted by 68LSS1

lol, because I got the one from Brothers and it has Early Classics logo stamped in the bottom of the crossmember.

oh my god...

that had me rolling

Joe67 · 07-30-2005, 04:30 PM

Quote:

Originally Posted by 68Stepbed

Copperhead isn't running the ECE crossmember. They advertised it on TRUCKS! TV after Copperhead was finished. It has a modified stock piece.

I had a friend modify his. He cut holes big enough for 3" pipe. Slid a piece of 3" pipe about 3-4" long and welded em in. He was only gonna use 2 1/4" pipe for his exhaust so he had plenty of clearance. I'm gonna do the same but I'll use bigger pipe so I can run 2 1/2" exhaust.

Welding a piece of pipe in actually strengthens the crossmember. Probably better than it was to begin with IMO.

Thanks for the clarification.
Here is the best pic I can find of Copperhead's setup. I should have looked closer when it was here in February

68LSS1 · 07-30-2005, 05:48 PM

One thing to note on Copperhead's exhaust design. Notice that the exhaust is attached to the drivetrain (except for whatever hangers are used aft of te mufflers). The headers are of course bolted to the heads and a hard bracket off the tranny for additional support. This allows the exhaust system to move with the drivetrain as opposed to being stressed when it gets "torqued" over. A good idea and well designed.

One other thing, I assumed a trailing arm suspension. If the truck is a leaf spring set up I wouldn't think twice. But as the trailing arms mount to that crossmember on the coil spring trucks I can't imagine what sort of stress that crossmember could be under especially subjected to launches and high hp/tq engines. Daily driver would probably be fine but I don't think I'd want to push it with a vehicle that also has weekend track duty.

*72longbed* · 07-31-2005, 09:51 PM

Here's what I would do:

First if you must cut holes in a crossmember that has trailing arms attached to it, cut the holes ROUND and at least 1/4" larger than the outside diameter of the exhaust pipe, (1/2" all the way around would be better). Next Fab up some pieces of 3/16" to 1/4" plate that have the same diameter hole cut through them. Make the plates as tall as you can, and still be able to weld them all the way around onto the crossmember and inside the hole. These 'scabbed' on plates will reinforce the crossmember at the exhaust pass through area and probably make it stronger than it was uncut.

Just my $.02
72longbed

DevinM · 08-02-2005, 10:06 PM

Thanks alot folks, I appreciate it greatly. I have trailing arms, so I WILL re-enforce the crossmember.
I especially like (2) ideas. 68Stepbed's suggestion of cutting 3" holes and welding 3" pipes in place. Cause, I will not be using anything larger than 2 1/2" pipes.
The other being plates, cut 1/4" larger than outside diameter the freshly cut holes, and welded in place.

07-28-2005, 09:17 PM	#1
DevinM Registered User Join Date: Jan 2002 Location: Deerfield, MA USA Posts: 198	Cutting holes in crossmember for exhaust. My truck is a "weekend driver" that only gets out when it's nice and sunny, and I drive less than 1000 miles a year. I don't race it, I just enjoy it. Now, that being said....I just purchased a set of 3/4 headers from ECE and want to cut holes in my existing crossmember to run the exhaust through. My truck is dropped 4/6 and my current long headers are too low and banged-up. Will I be OK? Should I re-enforce it? How would someone re-enforce it? __________________ '71 Chevy C-10 - Current '62 Imapla SS - Traded for my current '73 Nova Hatch - traded for ATC-350X '73 Chevelle Deluxe - First car (R.I.P) DEERFIELD, MA

07-28-2005, 10:41 PM	#2
Sweet72 Registered User Join Date: Nov 2003 Location: Alexandria, VA Posts: 1,534	Project CopperHead on Trucks TV had a cross-member that was cut and reinforced for the dual exhaust. I'm not sure what was used but it looked like a 1-2" section of 4-5" dia. pipe was welded into the holes to strengthen it. I think ECE offers a cross-member designed for lowered trucks. __________________ '72 GMC SWB C1500 Custom, frame-off in progress. 383 SBC, 9:1CR, Comp Cams XE262H, Scat internal balanced crank, Eagle SIR 6" rods, Keith Black dish pistons, Dart Iron Eagle 72/180 heads, Weiand Stealth intake, Stewart stage I water pump, Holley 4bbl vac sec, TH350 with B&M Shift Improver Kit. 12 bolt positraction.

07-28-2005, 11:05 PM	#3
DevinM Registered User Join Date: Jan 2002 Location: Deerfield, MA USA Posts: 198	Sweet72, I spoke with the guys over at ECE. I advised that I was tight (very tight) on money, and could only afford the headers. They told me that since my truck is not a "daily driver", I could cut holes in my existing crossmember and not have any issues. __________________ '71 Chevy C-10 - Current '62 Imapla SS - Traded for my current '73 Nova Hatch - traded for ATC-350X '73 Chevelle Deluxe - First car (R.I.P) DEERFIELD, MA

07-28-2005, 11:15 PM	#4
Tanker350 Account Suspended Join Date: Dec 2003 Location: Palm Desert, Ca Posts: 410	What about this? Attached Images

07-29-2005, 03:49 AM	#5
68LSS1 Registered User Join Date: Dec 2002 Location: Tampa Posts: 1,191	It probably would be OK as you state it's not a daily driver and you don't race it. But I don't think I'd ever feel comfortable without reinforcing the crossmember. Whether it be boxing it (which would be real easy but overkill) or just welding some plate over the hole and larger than what the hole will become. I've got the ECE crossmember pictured above and will be modifying it also as I don't trust it to stay together with what I plan on subjecting it to. __________________ '68 Short Step LS1/T56, Hydratech, Fatman Fabrications Stage III, Baer, Hot Rods to Hell, US Body, S&W, etc

07-29-2005, 10:21 AM	#6
matthufham Registered User Join Date: Feb 2005 Location: Carl Junction, Missouri Posts: 2,061	brothers and ece makes a kit, but they're for lowered rides. if you're at stock stance the crossmember's hole for the drive shaft would be too high.

07-29-2005, 11:19 AM	#8
FirstGen Just Don't Stop! Join Date: Feb 2004 Location: Dallas Posts: 1,239	mine is just a stock cut one and 600 rwhp later... no problem. __________________ 1968 C10 build in process TT LSA/6L90e/9"

07-29-2005, 12:55 PM	#10
CHEVYE my gas saver Join Date: Sep 2003 Location: Clarksville, TN Posts: 2,046	FirstGen's truck is definetely lowered. it's an awesome truck too with a ton of power. __________________ 85' SWB, 4.3/TH350, getting ready for paint 84`SWB, 462ci./TH400, cowl hood, 15" billet spec., flows, blazer buckets/console, flat black 71`SWB, project ebay feedback

07-29-2005, 01:34 PM	#12
Low69CST Registered User Join Date: May 2000 Location: Frankfort, Kentucky, USA Posts: 2,163	Didn't 3/4 tons come braced fromt he factory? You could find a pair of those out of a junk yard. You could also make and weld in some metal to box in the crossmemeber. Also, I think you'll have to mount the exhaust solid to the frame. That means you'll have to install flex joints like they did on Trucks. I'm not sure what they cost. __________________ '69 CST Short fleetside Lowered, 400 small block, 700R4, 4 wheel disc brakes, front sway bar & rear camaro sway bar (in progress) '87 V10 4x4 Short Fleetside Quad Suspension and Dual Tanks

07-29-2005, 05:10 PM	#15
matthufham Registered User Join Date: Feb 2005 Location: Carl Junction, Missouri Posts: 2,061	it probably did since ece basically provided everything for that truck.

07-29-2005, 11:33 PM	#16
68Stepbed Registered User Join Date: Mar 2005 Location: 10-Uh-See Posts: 5,609	Copperhead isn't running the ECE crossmember. They advertised it on TRUCKS! TV after Copperhead was finished. It has a modified stock piece. I had a friend modify his. He cut holes big enough for 3" pipe. Slid a piece of 3" pipe about 3-4" long and welded em in. He was only gonna use 2 1/4" pipe for his exhaust so he had plenty of clearance. I'm gonna do the same but I'll use bigger pipe so I can run 2 1/2" exhaust. Welding a piece of pipe in actually strengthens the crossmember. Probably better than it was to begin with IMO. __________________ Matt 68 C10 stepside, LS1/700R4, TCI Engineering suspension system

07-30-2005, 12:47 AM	#17
newin72 Account Suspended Join Date: May 2005 Location: East Texas Posts: 545	ok, I have every copperhead episode on the DVR, I will have to settle this! give me a little bit to go through them all and find it...

07-30-2005, 12:53 AM	#18
newin72 Account Suspended Join Date: May 2005 Location: East Texas Posts: 545	68stepbed is correct! man that's an awesome truck!

07-30-2005, 05:38 AM	#20
ACES Life is a gamble Join Date: Oct 2003 Location: Lee's Summit, MO Posts: 796	My truck has holes cut in the crossmemeber and its just fine. I do want to note, that I don't have much horsepower either. Here is a bad picture of it: __________________ 1970 Orange CST C-10 w/350, posi, Longbed The torpid artist seeks inspiration at any cost, by virtue or by vice, by friend or by fiend, by prayer or by wine. -- Ralph Waldo Emerson Last edited by ACES; 07-30-2005 at 05:44 AM.

07-30-2005, 05:48 PM	#23
68LSS1 Registered User Join Date: Dec 2002 Location: Tampa Posts: 1,191	One thing to note on Copperhead's exhaust design. Notice that the exhaust is attached to the drivetrain (except for whatever hangers are used aft of te mufflers). The headers are of course bolted to the heads and a hard bracket off the tranny for additional support. This allows the exhaust system to move with the drivetrain as opposed to being stressed when it gets "torqued" over. A good idea and well designed. One other thing, I assumed a trailing arm suspension. If the truck is a leaf spring set up I wouldn't think twice. But as the trailing arms mount to that crossmember on the coil spring trucks I can't imagine what sort of stress that crossmember could be under especially subjected to launches and high hp/tq engines. Daily driver would probably be fine but I don't think I'd want to push it with a vehicle that also has weekend track duty. __________________ '68 Short Step LS1/T56, Hydratech, Fatman Fabrications Stage III, Baer, Hot Rods to Hell, US Body, S&W, etc



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07-31-2005, 09:51 PM	#24
72longbed Account Suspended Join Date: Jun 2003 Location: PA Posts: 1,411	Just an Idea Here's what I would do: First if you must cut holes in a crossmember that has trailing arms attached to it, cut the holes ROUND and at least 1/4" larger than the outside diameter of the exhaust pipe, (1/2" all the way around would be better). Next Fab up some pieces of 3/16" to 1/4" plate that have the same diameter hole cut through them. Make the plates as tall as you can, and still be able to weld them all the way around onto the crossmember and inside the hole. These 'scabbed' on plates will reinforce the crossmember at the exhaust pass through area and probably make it stronger than it was uncut. Just my $.02 72longbed

08-02-2005, 10:06 PM	#25
DevinM Registered User Join Date: Jan 2002 Location: Deerfield, MA USA Posts: 198	Thanks alot folks, I appreciate it greatly. I have trailing arms, so I WILL re-enforce the crossmember. I especially like (2) ideas. 68Stepbed's suggestion of cutting 3" holes and welding 3" pipes in place. Cause, I will not be using anything larger than 2 1/2" pipes. The other being plates, cut 1/4" larger than outside diameter the freshly cut holes, and welded in place. __________________ '71 Chevy C-10 - Current '62 Imapla SS - Traded for my current '73 Nova Hatch - traded for ATC-350X '73 Chevelle Deluxe - First car (R.I.P) DEERFIELD, MA

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