Exhaust through crossmember? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

brans72 · 03-20-2013, 10:04 PM

How are you guy's cutting the 3 to 4 inch holes so nice for exhaust to run through in your factory crossmembers? Any ideas would be great and no plasma cutter here I wish!

TexasSteve · 03-20-2013, 10:11 PM

I saved these pics as ideas on how to do mine. Forget where I got them but I think off this site awhile back. 2 ideas in the pics......Through the crossmember & out through the side of the frame. Both good ideas but going outside the frame limits rear tire width. I'm fat rear tire kinda guy....

cubber · 03-21-2013, 12:03 AM

Hole saws work great.

**Tom Vogel** · 03-21-2013, 09:34 AM

Quote:

Originally Posted by cubber

Hole saws work great.

Thats what we used... worked excellent.

nicolas72gmc · 03-21-2013, 01:24 AM

Posted via Mobile Device

Here's a 5" hole with pipe and plate boxed around it. It's 3" exhaust thru the cross member.
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nicolas72gmc · 03-21-2013, 01:25 AM

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nicolas72gmc · 03-21-2013, 01:34 AM

I think they used a plasma cutter. Sorry, that doesn't help you much.
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Daaaanz67 · 03-21-2013, 09:49 AM

I used 3 inch hole saw. I drilled through a half inch ply wood and remove the round plugs inside of the bit. You will need two plugs which are now used as guides. Then I drilled out the center of the plugs for a 7/16 bolt. I then sandwhich the frame with the plugs. Make sure you use some flat washer on the head and nut side. After I get the plugs clamped on the frame I then remove the center drill bit on the hole saw. Now the saw will spin around the plugs and cut through the steal. Just make sure you center the plus as not to cut through the holes for the brake cable. Hope you can understand this good luck it's easier than you think take you time. Mine turned out great

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**special-K** · 03-21-2013, 02:20 PM

Quote:

Originally Posted by Daaaanz67

I used 3 inch hole saw. I drilled through a half inch ply wood and remove the round plugs inside of the bit. You will need two plugs which are now used as guides. Then I drilled out the center of the plugs for a 7/16 bolt. I then sandwhich the frame with the plugs. Make sure you use some flat washer on the head and nut side. After I get the plugs clamped on the frame I then remove the center drill bit on the hole saw. Now the saw will spin around the plugs and cut through the steal. Just make sure you center the plus as not to cut through the holes for the brake cable. Hope you can understand this good luck it's easier than you think take you time. Mine turned out great

What size hole saw & pipe did you use? In your description I am thinking you bolted the plugs (donut hole) through the center to the frame as a guide but in the picture I see the cut-out bolted. I'm not following

LEX · 03-21-2013, 09:59 AM

Here are a couple pics that I saved to give you an idea.

Daaaanz67 · 03-21-2013, 10:12 AM

That's a good idea, I just did the opposite and used the center plugs as my guide.
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Rctreadaway · 03-21-2013, 03:21 PM

I'm going with sch 40 4" i.d. steel pipe. Walls are roughly .25" thick so I'm going with a 4.5" hole saw. I'm going to tackle it tomorrow evening since I'm having my exhaust done Monday. Just picked up the saw with arbor from Lowe's for forty bucks. should save me a bunch or work since I don't have a plasma cutter!
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**special-K** · 03-21-2013, 04:30 PM

I have 4" schedule 40 pipe. Isn't that 4" O.D? I'm pretty sure I used a 4" hole saw last time.

Rctreadaway · 03-21-2013, 04:37 PM

The guy at the machine shop I got it from asked me specifically if I wanted 4" inside or outside and I told him inside. I didn't second guess him. hopefully we were on the same page and I got the right saw lol.
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POPO1984 · 03-21-2013, 05:35 PM

I welded a price of thin metal over the center of the area to be cut out. Then marked the center and used that to center my drill bit for guiding the hole saw
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Daaaanz67 · 03-21-2013, 07:24 PM

Special K I used the I guess you would call it the donut hole to clamp to the frame. I called it plugs because it would be the round piece that you would knock out of the actual hole saw after you drill through the plywood. The cut out was not done by me it was by lex the post below mine. I used what I believe was a 3" Id hole saw but if you actually measured the od I think it measured out to approximately 3" 1/8 I hope that answered your question. When I get back to the shop i will look for those plugs and post pictures.
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Daaaanz67 · 03-21-2013, 07:33 PM

Oh yeah forgot to mention that the pipe I used was thin wall so the od ended being 3 1/8" which eded up the same diameter as the hole saw.
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Number98 · 05-19-2013, 07:32 PM

Quote:

Originally Posted by Daaaanz67

Oh yeah forgot to mention that the pipe I used was thin wall so the od ended being 3 1/8" which eded up the same diameter as the hole saw.
Posted via Mobile Device

I assume your running 2-1/2" exhaust?

sleeper69 · 03-21-2013, 07:53 PM

not sure on the sizes exactly but i also just used a hole saw. slow but just buy some beer and it works perfect!

vidman · 05-19-2013, 07:11 PM

Just cut my crossmember today. Used a 4 1/2 starret hole saw and going to weld in some scheduled 40 pipe. I put them in the lathe to make them purdy. About 2 hours drilling and lathe time..

ehill83nc · 05-20-2013, 07:30 PM

Im going to do this same thing to my frame. Glad I saw this!

leftybass209 · 05-20-2013, 08:25 PM

I love the few different ideas for how people have done this. Has anyone had any problems with the parking brake cable while running the exhaust through the cross member?

Lee H · 05-20-2013, 09:59 PM

Quote:

Originally Posted by leftybass209

I love the few different ideas for how people have done this. Has anyone had any problems with the parking brake cable while running the exhaust through the cross member?

No, the cable is now below the exhaust instead of over.
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leftybass209 · 05-21-2013, 12:08 AM

Thanks Lee H!!! You answered my question and gave me more work to do. Fortunately my cab is coming off in a week or so, that should make it easier to accomplish this task.

ehill83nc · 05-20-2013, 09:56 PM

Thats a question I would like to know also. Does it interfere with the parking brake cable?

03-20-2013, 10:04 PM	#1
brans72 Registered User Join Date: Dec 2009 Location: Durham,NC Posts: 636	Exhaust through crossmember? How are you guy's cutting the 3 to 4 inch holes so nice for exhaust to run through in your factory crossmembers? Any ideas would be great and no plasma cutter here I wish!

03-20-2013, 10:11 PM	#2
TexasSteve Registered User Join Date: Feb 2013 Location: Bertram, TX Posts: 103	Re: Exhaust through crossmember? I saved these pics as ideas on how to do mine. Forget where I got them but I think off this site awhile back. 2 ideas in the pics......Through the crossmember & out through the side of the frame. Both good ideas but going outside the frame limits rear tire width. I'm fat rear tire kinda guy.... Attached Images __________________ 2001 Yukon Factory Grey Metallic~2" DJM Key front drop/3" DJM Rear Springs~stock 16" chrome steel wheels~5.3/4L60E~Volante CAI w/under bumper air scoop~Magnaflow 10426 Bullet muffler~DDM LED all exterior lighting/55w-5000k HID Hi/Low/35w Fog

03-21-2013, 12:03 AM	#3
cubber Registered User Join Date: Mar 2012 Location: Leanna, TN Posts: 2,061	Re: Exhaust through crossmember? Hole saws work great. __________________ =MATTHEW 69 Stepper...Stroked & Bagged GONE BUT NOT FORGOTTEN 2003 Chevrolet Z71 Ext. Cab 1995 Cavalier gas saver!

03-21-2013, 01:24 AM	#5
nicolas72gmc Registered User Join Date: Aug 2008 Location: Sunny Arizona Posts: 525	Re: Exhaust through crossmember? Posted via Mobile Device Here's a 5" hole with pipe and plate boxed around it. It's 3" exhaust thru the cross member. Posted via Mobile Device Attached Images __________________ Nick "Everyone has a plan, 'till they get punched in the mouth".........Mike Tyson 1968, GMC, SWB, Project 1972, GMC, LWB, Daily Driver, 383, headers, 2.5"/3" exhaust, 200r4, 3.5/5 ECE components. 1972, C/10, LWB, 350 vortec, th350

03-21-2013, 01:25 AM	#6
nicolas72gmc Registered User Join Date: Aug 2008 Location: Sunny Arizona Posts: 525	Re: Exhaust through crossmember? Posted via Mobile Device Attached Images __________________ Nick "Everyone has a plan, 'till they get punched in the mouth".........Mike Tyson 1968, GMC, SWB, Project 1972, GMC, LWB, Daily Driver, 383, headers, 2.5"/3" exhaust, 200r4, 3.5/5 ECE components. 1972, C/10, LWB, 350 vortec, th350

03-21-2013, 01:34 AM	#7
nicolas72gmc Registered User Join Date: Aug 2008 Location: Sunny Arizona Posts: 525	Re: Exhaust through crossmember? I think they used a plasma cutter. Sorry, that doesn't help you much. Posted via Mobile Device __________________ Nick "Everyone has a plan, 'till they get punched in the mouth".........Mike Tyson 1968, GMC, SWB, Project 1972, GMC, LWB, Daily Driver, 383, headers, 2.5"/3" exhaust, 200r4, 3.5/5 ECE components. 1972, C/10, LWB, 350 vortec, th350

03-21-2013, 09:49 AM	#8
Daaaanz67 Registered User Join Date: Nov 2011 Location: Idaho Posts: 857	Re: Exhaust through crossmember? I used 3 inch hole saw. I drilled through a half inch ply wood and remove the round plugs inside of the bit. You will need two plugs which are now used as guides. Then I drilled out the center of the plugs for a 7/16 bolt. I then sandwhich the frame with the plugs. Make sure you use some flat washer on the head and nut side. After I get the plugs clamped on the frame I then remove the center drill bit on the hole saw. Now the saw will spin around the plugs and cut through the steal. Just make sure you center the plus as not to cut through the holes for the brake cable. Hope you can understand this good luck it's easier than you think take you time. Mine turned out great Posted via Mobile Device

03-21-2013, 09:59 AM	#10
LEX Registered User Join Date: Oct 2011 Location: Houston, Texas Posts: 884	Re: Exhaust through crossmember? Here are a couple pics that I saved to give you an idea.

03-21-2013, 10:12 AM	#11
Daaaanz67 Registered User Join Date: Nov 2011 Location: Idaho Posts: 857	Re: Exhaust through crossmember? That's a good idea, I just did the opposite and used the center plugs as my guide. Posted via Mobile Device

03-21-2013, 03:21 PM	#12
Rctreadaway Registered User Join Date: Jan 2013 Location: Monroe, NC Posts: 39	Re: Exhaust through crossmember? I'm going with sch 40 4" i.d. steel pipe. Walls are roughly .25" thick so I'm going with a 4.5" hole saw. I'm going to tackle it tomorrow evening since I'm having my exhaust done Monday. Just picked up the saw with arbor from Lowe's for forty bucks. should save me a bunch or work since I don't have a plasma cutter! Posted via Mobile Device

03-21-2013, 04:30 PM	#13
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,852	Re: Exhaust through crossmember? I have 4" schedule 40 pipe. Isn't that 4" O.D? I'm pretty sure I used a 4" hole saw last time. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

03-21-2013, 04:37 PM	#14
Rctreadaway Registered User Join Date: Jan 2013 Location: Monroe, NC Posts: 39	Re: Exhaust through crossmember? The guy at the machine shop I got it from asked me specifically if I wanted 4" inside or outside and I told him inside. I didn't second guess him. hopefully we were on the same page and I got the right saw lol. Posted via Mobile Device

03-21-2013, 05:35 PM	#15
POPO1984 Registered User Join Date: Jul 2009 Location: Houston, Tx Posts: 1,133	Re: Exhaust through crossmember? I welded a price of thin metal over the center of the area to be cut out. Then marked the center and used that to center my drill bit for guiding the hole saw Posted via Mobile Device __________________ 1972 SWB Medium Olive South Houston Instagram: Antbish84

03-21-2013, 07:24 PM	#16
Daaaanz67 Registered User Join Date: Nov 2011 Location: Idaho Posts: 857	Re: Exhaust through crossmember? Special K I used the I guess you would call it the donut hole to clamp to the frame. I called it plugs because it would be the round piece that you would knock out of the actual hole saw after you drill through the plywood. The cut out was not done by me it was by lex the post below mine. I used what I believe was a 3" Id hole saw but if you actually measured the od I think it measured out to approximately 3" 1/8 I hope that answered your question. When I get back to the shop i will look for those plugs and post pictures. Posted via Mobile Device

03-21-2013, 07:33 PM	#17
Daaaanz67 Registered User Join Date: Nov 2011 Location: Idaho Posts: 857	Re: Exhaust through crossmember? Oh yeah forgot to mention that the pipe I used was thin wall so the od ended being 3 1/8" which eded up the same diameter as the hole saw. Posted via Mobile Device



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03-21-2013, 07:53 PM	#19
sleeper69 Registered User Join Date: Feb 2013 Location: Arundel, Maine Posts: 11	Re: Exhaust through crossmember? not sure on the sizes exactly but i also just used a hole saw. slow but just buy some beer and it works perfect!

05-19-2013, 07:11 PM	#20
vidman Registered User Join Date: Jun 2012 Location: Fitchburg,Mass Posts: 737	Re: Exhaust through crossmember? Just cut my crossmember today. Used a 4 1/2 starret hole saw and going to weld in some scheduled 40 pipe. I put them in the lathe to make them purdy. About 2 hours drilling and lathe time.. Attached Images __________________ 62 Willys 4wd Pickup : 72 C-10 swb 504 stroker 09 Taco 3" lift 33" tires: 90 K-5 blazer (plow truck): RIP Ross Little brother

05-20-2013, 07:30 PM	#21
ehill83nc Registered User Join Date: Apr 2013 Location: Winston Salem, NC Posts: 42	Re: Exhaust through crossmember? Im going to do this same thing to my frame. Glad I saw this!

05-20-2013, 08:25 PM	#22
leftybass209 Registered User Join Date: Feb 2011 Location: Modesto, CA Posts: 2,189	Re: Exhaust through crossmember? I love the few different ideas for how people have done this. Has anyone had any problems with the parking brake cable while running the exhaust through the cross member?

05-21-2013, 12:08 AM	#24
leftybass209 Registered User Join Date: Feb 2011 Location: Modesto, CA Posts: 2,189	Re: Exhaust through crossmember? Thanks Lee H!!! You answered my question and gave me more work to do. Fortunately my cab is coming off in a week or so, that should make it easier to accomplish this task.

05-20-2013, 09:56 PM	#25
ehill83nc Registered User Join Date: Apr 2013 Location: Winston Salem, NC Posts: 42	Re: Exhaust through crossmember? Thats a question I would like to know also. Does it interfere with the parking brake cable?

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