Another exhaust question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

rauto13 · 10-07-2005, 12:52 AM

I want to tuck the exhaust on my truck as high as possible. I have a 72 LWB with trailing arms. I plan on lowering the truck soon. I am wanting to cut 3" holes in the trailing arm crossmember so that I can run 2 1/2 " exhaust over the trans crossmember and through the trailing arm crossmember. I have already redone the shift linkage, so that would not be in the way.

Is this okay to do, or will I weaken the trailig arm crossmember too much?

Could I weld some plate in and strengthen this area, or possibly box the crossmember?

Any input is greatly appreciated.

I am also looking for headers that will tuck as close to the floorboards as possible.

I am tired of looking at the exhaust system hanging down.

Tx Firefighter · 10-07-2005, 06:58 AM

That's a common technique for get the exhaust higher. I usually just cut the holes in the crossmember and be done with it. Some other guys like to cut the holes then plate it and reinforce it like you suggested. I've never seen or heard of any problems either way.

ACES · 10-07-2005, 07:08 AM

This is how my exhaust is routed:

djracer · 10-07-2005, 07:36 AM

I'd put a short piece of pipe in the hole and weld it in then run the exhaust through the pipe!

72MARIO · 10-07-2005, 08:18 AM

Dynomax Chevelle shorty's will fit. But they have small primarys 1 1/2" o 2 1/2" collector. They should be fine if you have a mild 350. I went with the heddman(sp) Chevelle shortys they are 1 5/8 to 3" I had to use North West Auto fabs motor mounts because they hit the stock motor mounts. Sure you could hack them out to clear but thats not good enough for me.

10-07-2005, 12:52 AM	#1
rauto13 saving one more Join Date: Sep 2005 Location: Pryor Creek, Oklahoma Posts: 3,066	Another exhaust question I want to tuck the exhaust on my truck as high as possible. I have a 72 LWB with trailing arms. I plan on lowering the truck soon. I am wanting to cut 3" holes in the trailing arm crossmember so that I can run 2 1/2 " exhaust over the trans crossmember and through the trailing arm crossmember. I have already redone the shift linkage, so that would not be in the way. Is this okay to do, or will I weaken the trailig arm crossmember too much? Could I weld some plate in and strengthen this area, or possibly box the crossmember? Any input is greatly appreciated. I am also looking for headers that will tuck as close to the floorboards as possible. I am tired of looking at the exhaust system hanging down. __________________ 72 Chevy longbed - now for parts 69 Chevy short fleet - needing some love 70 RS Camaro - needing more love driver - 96 GMC X-cab

10-07-2005, 06:58 AM	#2
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	That's a common technique for get the exhaust higher. I usually just cut the holes in the crossmember and be done with it. Some other guys like to cut the holes then plate it and reinforce it like you suggested. I've never seen or heard of any problems either way. __________________ I'm on the Instagram- @Gearhead_Kevin

10-07-2005, 07:08 AM	#3
ACES Life is a gamble Join Date: Oct 2003 Location: Lee's Summit, MO Posts: 796	Here is mine This is how my exhaust is routed: __________________ 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

10-07-2005, 07:36 AM	#4
djracer Registered User Join Date: Feb 2001 Location: Wetumpka, Al, U.S. Posts: 8,891	I'd put a short piece of pipe in the hole and weld it in then run the exhaust through the pipe! __________________ Kevin Special Thanks to All who have helped on the TRUCK! My Pass Time Show http://s129.photobucket.com/albums/p...Chapter1-0.mp4 So Far my best Times are: Motor only: 6.44 1/8 @ 104.13 10.39 1/4 @ 125.83 Nitrous Times: 5.785 1/8 @ 118.65 with a 1.336 60ft 9.168 1/4 @ 142.58 with a 250 shot dead out of the hole!

10-07-2005, 08:18 AM	#5
72MARIO Registered User Join Date: Nov 2000 Location: Huntsville Ontario Canada Posts: 4,052	Dynomax Chevelle shorty's will fit. But they have small primarys 1 1/2" o 2 1/2" collector. They should be fine if you have a mild 350. I went with the heddman(sp) Chevelle shortys they are 1 5/8 to 3" I had to use North West Auto fabs motor mounts because they hit the stock motor mounts. Sure you could hack them out to clear but thats not good enough for me. __________________ 1968 Suburban numbers matching all original truck now equipped with 6.0/4L80 on Accuair http://67-72chevytrucks.com/vboard/s...d.php?t=625017 1967 C/20 6.0/4L80 Roofing Truck 1990 V2500 Suburban "Plow Truck" 2005 TAHOE DD

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