Rear Frame Rail Notching How To!

[dlafont]

Hey DonWG,

I like your UCA to LCA link. Are you willing to share the materials/drawings to make one of these up? I like what I see and I want to do this .

The frame mounting support bars.

 

[Hot Air]

FWIW, Hotchkis makes a similar piece! Check out Summit or Jegs or a Buick vendor.
Conrad

 

[Alky V6]

If you want a straight cut, tack weld a straight edge onto the frame to use as a guide. Might take a lil time to set up right, but it will cut way down on grinding time. Hell, if you can get the straight edge to clamp on and not get in your way then that saves even more time!

What I ended up doing was using a piece of 1/2 x 1/2 angle and cutting notches along the length of one edge, every 1 inch. This allowed me to bend the piece to the contour of the frame and tack weld it in place. This gave me a very wide edge to use as a guide for the cut. When I was done with the cut, I removed the piece by grinding the tack welds, re-bent it and tacked it in place for the next cut. All cuts are completed. Some cleanup grinding is next.

 

[Alky V6]

Hey DonWG,

I like your UCA to LCA link. Are you willing to share the materials/drawings to make one of these up? I like what I see and I want to do this .

I would take Conrad's advice and get the Hotchkis bars. The only reason I made my own was because I was in a hurry and wanted to get on with this project without having to wait for another part in the mail.
I made my bars straight with no bend in them. I didn't like the idea of putting a bend in the bar. A straight shot is stronger. Don't know how strong it really needs to be. The straight shot meant that I needed to do some body work to the seat tubs as you can see in the pics. There are no drawings. It was a design-on-the-fly project.

If you still want to do your own, I can put a materials list together.

 

[dlafont]

I guess you are talking about these:

Hotchkis Sport Suspension - 78-88 GM A/G Body Trailing Arm Mount Braces :: Rear Suspension :: Trailing Arm Braces

Correct?

Don

 

[Alky V6]

I guess you are talking about these:

Hotchkis Sport Suspension - 78-88 GM A/G Body Trailing Arm Mount Braces :: Rear Suspension :: Trailing Arm Braces

Correct?

Don

Yes. That's what you want.

 

[Louie L.]

DW,
I havent checked this thread out for a while. First off... awesome work. I like the way you think when dont over analyze..lol

That brace is kik ass..I thought of building one just like it, just didnt know how much clearance i would have to create at the seat buck3t. Doesnt seem like alot.

It may be too late now, but the current location of your anti roll bar will limit how low you can go if you ever want to be low. I dont know if you are lowering the car too. But As the car gets lower , the uppers get closer to the anti roll bar. Mine is in the same location.

This is an issue that im currently dealing with. The ridiculously high upper control arm bushings brackets done by Moser creates even more of an interference when going low.


Here is my car at its current stance for reference. I have no interference at this time , but the rear can be at least 3/4 to 1 in lower if i remove the spring spacers.

 

[cruzn57]

Louie

I think you went with 150lb springs on the rear, were they enough?
or did you have to use some spring rubbers?
5in dia? or 7 in dia?
I'm adding a dirt track style adjustable spring preload, very simple, very cheap,
when I check'd rear wheel weights, had 40lbs diff!
can jack wheel weight like nascar!

 

[SS_Sean]

I think people tend to over-analyze this stuff. The frame notch I did on my 78 malibu I used the original frame skins. I split the frame at the weld and cut the smaller frame C down and slid it back into the knocks and welded. Done.

The bracing cross-wise is an inner frame rail to inner frame rail anti-roll bar from TRZ. I put my ARB at the back of the diff housing, facing forward. I clipped the rear ends of the spring pockets off and welded the ARB bar in right there. The spring pocket and frame lend the bar some serious support since the bar is now being connected at two points.

Granted the cage is a twelve point, with connection points the top of the spring pocket/frame, and rear cross member. I added a rear cross member the the far rear of the car to tie the frame together, since the rear bumper of gbodies is actually a part of the frame. I went to fiberglass bumpers

That's it. No more. No less. If anyone is interested in pics then let me know. I have been a 10.49@128, and intend on 9.8x's next year with no changes. Good to go!

 

[Alky V6]

I think people tend to over-analyze this stuff. The frame notch I did on my 78 malibu I used the original frame skins. I split the frame at the weld and cut the smaller frame C down and slid it back into the knocks and welded. Done.

The bracing cross-wise is an inner frame rail to inner frame rail anti-roll bar from TRZ. I put my ARB at the back of the diff housing, facing forward. I clipped the rear ends of the spring pockets off and welded the ARB bar in right there. The spring pocket and frame lend the bar some serious support since the bar is now being connected at two points.

Granted the cage is a twelve point, with connection points the top of the spring pocket/frame, and rear cross member. I added a rear cross member the the far rear of the car to tie the frame together, since the rear bumper of gbodies is actually a part of the frame. I went to fiberglass bumpers

That's it. No more. No less. If anyone is interested in pics then let me know. I have been a 10.49@128, and intend on 9.8x's next year with no changes. Good to go!

I think I remember seeing some pics of your setup. I remember the TRZ roll bar mounted rear of the axle housing. You're more than welcome to post some pics of your setup.

 

[Alky V6]

DW,
I havent checked this thread out for a while. First off... awesome work. I like the way you think when dont over analyze..lol

That brace is kik ass..I thought of building one just like it, just didnt know how much clearance i would have to create at the seat buck3t. Doesnt seem like alot.

It may be too late now, but the current location of your anti roll bar will limit how low you can go if you ever want to be low. I dont know if you are lowering the car too. But As the car gets lower , the uppers get closer to the anti roll bar. Mine is in the same location.

This is an issue that im currently dealing with. The ridiculously high upper control arm bushings brackets done by Moser creates even more of an interference when going low.


Here is my car at its current stance for reference. I have no interference at this time , but the rear can be at least 3/4 to 1 in lower if i remove the spring spacers.

I know what you mean about the clearance, uca to roll bar. I spotted that already. I don't think I'll be lowering the car. I'm looking for a rear stance that is identical to the pic you posted. Are you running 29.5" tires? Your car looks way cool! Any runs with it yet?

You mentioned the Moser rear housing. I'm running one of their 12 bolt housings. Your post wasn't clear. Are you running one now without clearance issues?

 

[SS_Sean]

I think I remember seeing some pics of your setup. I remember the TRZ roll bar mounted rear of the axle housing. You're more than welcome to post some pics of your setup.

I'll post a couple up. In actuality, though, your setup is exactly like mine except the difference in the ARB's mounting direction. You're going to like that results from that ARB, too. My 60's went from 1.58 average to 1.48 with the only changes being the bar and loosing up the front end...

 

[Louie L.]

I know what you mean about the clearance, uca to roll bar. I spotted that already. I don't think I'll be lowering the car. I'm looking for a rear stance that is identical to the pic you posted. Are you running 29.5" tires? Your car looks way cool! Any runs with it yet?

You mentioned the Moser rear housing. I'm running one of their 12 bolt housings. Your post wasn't clear. Are you running one now without clearance issues?

DW,
I run 295/65 MT DRs, they are just over 29in tall. The tire is so tall that it doesnt look that low but it is. I have no clearance issues on mine.
Clearance is tight , but no rubbing of any sort even thru some crazy tire shake in the 1/8 mile. I have all but eliminated the wheel well lip and streched the factory tubs about 1 inch. I finally got some solid runs shaking the car down at BG. 8.96 @161.7 on 20 psi and mild timing. 60 ft was only 1.65 leaving soft to make sure we go down track.

I use a Moser 9in rear. I have noticed that on the moser 12 bolts the bushing are correct, but go to a 9in and they are high..

 

[Louie L.]

I think you went with 150lb springs on the rear, were they enough?
or did you have to use some spring rubbers?
5in dia? or 7 in dia?
I'm adding a dirt track style adjustable spring preload, very simple, very cheap,
when I check'd rear wheel weights, had 40lbs diff!
can jack wheel weight like nascar!

Yes I used 12-150 springs. The rate appears to be fine. The only issue is the inteference i described above. I had to use to teflon 3/4 or 1 in spacers i had laying around. Im thinking of relocating the bar and taking the spacers out.

I too considered the weight jackers for adjsuring the ride height, but i like it low so i scrapped the idea.

 

[Louie L.]

DW,
Can you post shome pics of that X member- brace you fabbed up under the car ?

 

[Alky V6]

DW,
Can you post shome pics of that X member- brace you fabbed up under the car ?

Sure. I'll take some pics of it tomorrow. Thanks for sharing the info. Sounds like you have a real monster on your hands. Congratulations.

 

[lazaris]

Louie,

You can have brackets made for the 9" housing and shorter upper control arms to put them where you want. I did that on mine and also added 4 adjustment holes. If you like I'll send you some pics.

DW,
I run 295/65 MT DRs, they are just over 29in tall. The tire is so tall that it doesnt look that low but it is. I have no clearance issues on mine.
Clearance is tight , but no rubbing of any sort even thru some crazy tire shake in the 1/8 mile. I have all but eliminated the wheel well lip and streched the factory tubs about 1 inch. I finally got some solid runs shaking the car down at BG. 8.96 @161.7 on 20 psi and mild timing. 60 ft was only 1.65 leaving soft to make sure we go down track.

I use a Moser 9in rear. I have noticed that on the moser 12 bolts the bushing are correct, but go to a 9in and they are high..

 

[Louie L.]

Louie,

You can have brackets made for the 9" housing and shorter upper control arms to put them where you want. I did that on mine and also added 4 adjustment holes. If you like I'll send you some pics.

Id loce to see the pics. This sounds like what TRZ is wanting to do for me, but they are still working on the jig in order to get these jobs in and out.

 

[ijames]

These sound like the brackets and upper arms that KevinS just introduced for the 8.5 and 12 bolt. I'm sure he's working on the 9" version . http://www.turbobuick.com/forums/ad...1-welcome-kevins-baselinesuspensions-com.html

 

[Alky V6]

Kevin's kit wouldn't work with Louie's 9" with the high axle housing mounting location unless there was room on the brackets to add a few holes higher than the stock location. That would also make clearance with his roll bar more of a problem.