Modifying front crossmember to shave weight. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Super73 · 04-09-2008, 10:35 PM

I've decided that I am going to modify my front cross member in order to shave more weight.

I'm going to level the truck on jackstands.
Remove the front clip.
Remove the front tires and lower control arms.
Tach weld some arms off the frame to the area the lower control arm bolts to the crossmember. (I'll need to actually make this removable)
Drill some holes in some flat stock that match the LCA u-bolts and weld on to the arms in the LCA location.
There is my jig..

Unbolt the jig.
Unbolt the crossmember.
Plasma cut the cross member off the spring holders.
Bolt the spring holders back on the other frame
Bolt the jig back on the frame
Take some 1/4" plate and drill holes that match the LCA hole location and bolt that to the jig
Cut some 2x4 square tube forming the new x-member
Weld that up to the spring holders and the Plate that matched the LCA holes
Make a set of motor mounts.

I would assume I can shave a decent amount of weight by doing so..

**regan wilson** · 04-09-2008, 11:41 PM

I'm sure you will save a little weight but most of the weight is in the lower control arm,steering box, and the spindle and brakes . I have a stock type front end with a pretty hacked up crossmember (i can pull the oil pan straight down). I have a rack & pinion and Strange built me some brakes for my spindles . The brakes were worth 70 pounds .

djracer · 04-10-2008, 06:19 AM

I like my bolt on Fatman mustang II setup!

**regan wilson** · 04-10-2008, 04:24 PM

If it werent for my headers I would have converted mine to a Fatman . They have such a narrow track it would put my tires into the headers . I also might have had to rebuild the header where the steering shaft goes through . My frontend weighs about 200 pounds so it aint too bad .

Super73 · 04-10-2008, 08:48 PM

Do you mind me asking what the brakes cost you? This is something I have been wanting to do. Are they race only brakes or could I still use them on the street?

BADGMC · 04-11-2008, 07:39 PM

Yep, the brakes, lca's, and spindles are the real killers for weight on the front. I just had the crossmember out on my 85 and it was a lot lighter than I ever thought it would be so I just blasted and painted it and put it back on.

djracer · 04-12-2008, 05:36 AM

don't buy djm lca's to lose weight! I think they weigh more than stock!

**regan wilson** · 04-15-2008, 05:14 PM

Quote:

Originally Posted by Super73

Do you mind me asking what the brakes cost you? This is something I have been wanting to do. Are they race only brakes or could I still use them on the street?

They were around $900.00 . Only a hundred or two more than a kit for a camaro . I have race rotors but I'm sure they would have one that would work on the street .

04-09-2008, 10:35 PM	#1
Super73 Registered User Join Date: Nov 2007 Location: Bay Area, Ca Posts: 2,841	Modifying front crossmember to shave weight. I've decided that I am going to modify my front cross member in order to shave more weight. I'm going to level the truck on jackstands. Remove the front clip. Remove the front tires and lower control arms. Tach weld some arms off the frame to the area the lower control arm bolts to the crossmember. (I'll need to actually make this removable) Drill some holes in some flat stock that match the LCA u-bolts and weld on to the arms in the LCA location. There is my jig.. Unbolt the jig. Unbolt the crossmember. Plasma cut the cross member off the spring holders. Bolt the spring holders back on the other frame Bolt the jig back on the frame Take some 1/4" plate and drill holes that match the LCA hole location and bolt that to the jig Cut some 2x4 square tube forming the new x-member Weld that up to the spring holders and the Plate that matched the LCA holes Make a set of motor mounts. I would assume I can shave a decent amount of weight by doing so..

04-09-2008, 11:41 PM	#2
regan wilson Senior Member Join Date: Mar 2008 Location: tyler texas Posts: 1,536	Re: Modifying front crossmember to shave weight. I'm sure you will save a little weight but most of the weight is in the lower control arm,steering box, and the spindle and brakes . I have a stock type front end with a pretty hacked up crossmember (i can pull the oil pan straight down). I have a rack & pinion and Strange built me some brakes for my spindles . The brakes were worth 70 pounds . __________________ NHRA Super Street 469C It only runs 10.90 at 156 mph

04-10-2008, 06:19 AM	#3
djracer Registered User Join Date: Feb 2001 Location: Wetumpka, Al, U.S. Posts: 8,891	Re: Modifying front crossmember to shave weight. I like my bolt on Fatman mustang II setup! __________________ 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!

04-10-2008, 04:24 PM	#4
regan wilson Senior Member Join Date: Mar 2008 Location: tyler texas Posts: 1,536	Re: Modifying front crossmember to shave weight. If it werent for my headers I would have converted mine to a Fatman . They have such a narrow track it would put my tires into the headers . I also might have had to rebuild the header where the steering shaft goes through . My frontend weighs about 200 pounds so it aint too bad . __________________ NHRA Super Street 469C It only runs 10.90 at 156 mph

04-10-2008, 08:48 PM	#5
Super73 Registered User Join Date: Nov 2007 Location: Bay Area, Ca Posts: 2,841	Re: Modifying front crossmember to shave weight. Do you mind me asking what the brakes cost you? This is something I have been wanting to do. Are they race only brakes or could I still use them on the street?

04-11-2008, 07:39 PM	#6
BADGMC Registered User Join Date: Jan 2004 Location: Duluth, Mn Posts: 162	Re: Modifying front crossmember to shave weight. Yep, the brakes, lca's, and spindles are the real killers for weight on the front. I just had the crossmember out on my 85 and it was a lot lighter than I ever thought it would be so I just blasted and painted it and put it back on. __________________ 85 GMC 1/2 ton LWB 4150lbs. 383 SBC with Twin MPT70 Turbos 850 CSU carb TH375 3.70 gears Ultimate 10" Converter 10.11@136.6 with 1.64 60ft. on 10.5-31-15W

04-12-2008, 05:36 AM	#7
djracer Registered User Join Date: Feb 2001 Location: Wetumpka, Al, U.S. Posts: 8,891	Re: Modifying front crossmember to shave weight. don't buy djm lca's to lose weight! I think they weigh more than stock! __________________ 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! Last edited by djracer; 04-16-2008 at 01:47 AM.



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