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Old 06-13-2022, 06:56 PM
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Default Front Clip Shimming

In general these questions apply to an A body.

Are core supports ever shimmed to raise or lower one side or the other? I assume if so it has to be done at the frame mount?

Are fenders ever shimmed between the core support and fender at the front two, top bolt holes?

I'm finding a difference in height between the left and right side of the core support that cannot be accounted for elsewhere on the frame/suspension. There is the possibility the frame horn on one side is slightly tweaked from a minor accident I had 40+ years ago ... maybe 3/8".

Thanks

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Old 06-13-2022, 07:49 PM
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Frame horn to datum, or floor, with car on even ( verified) jack stands.
On F bodys the core is shimmed at mounting where it hangs off bottom of frame

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Old 06-13-2022, 08:23 PM
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The core supports are definitely shimmed on 64-65 A-bodies.

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Old 06-13-2022, 08:59 PM
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My POS repro core support was a different height on the DS compared to the PS...was having a hard time getting the fender to door gap and hood gaps correct and I finally figured out the core needed to come up on that side.

I took the steel insert out of the DS bushing and cut 3/8" off in the lathe and after tightening it all up the gaps were better.

May not be your issue, but thought I would mention it. Bringing the core up seemed like a better choice than shimming up the fender.

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Old 06-13-2022, 08:59 PM
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Yes, yes, no.

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Old 06-13-2022, 09:42 PM
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I had problems with my passenger side and had to shim the core support on that side to get my fender to door to hood to endure front bumper correct.

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Old 06-14-2022, 01:09 AM
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Thanks folks ... yes it is a repop core support. I can cut the frame mount steel tube length no problem.
Now I have to try to figure out whether it needs to go up on the low side, or down on the high side Guess I might have to wait until the fenders are mounted to do that. At this point I just happened to notice it while working on something else.

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Old 06-14-2022, 08:37 AM
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Agree with formula Bruce. I would install the core support, make sure the front of the car is sitting in true plane and then measure the core to verify it is square/level in plane as well. Once you know that part is right the rest should be a bit easier to align. Something I do when putting together the front of the f body is to make a couple of gauge sticks just slightly wider than the hood itself and put them in between the fenders at the font and back as a spacer. Also find a couple of points and make sure the hood opening area is square by measuring on a diagonal before you bolt everything down.

First time I did the job I had both fenders installed perfect as far as alignment and gaps were concerned, the nose piece aligned perfect. When I went to set the hood I found things were way out of square and I had to start all over!!

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Old 06-14-2022, 11:12 AM
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Thank you, you just gave me the way to figure out some things I was worried about. Specially the hood. The sticks are a great idea.

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Old 06-14-2022, 12:03 PM
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Some have found this thread helpful.

http://forums.maxperformanceinc.com/...d.php?t=773122

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Old 06-14-2022, 12:06 PM
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If your front horn is bent you have no choice but to shim it, I used a repop core support as well but when I measured from the mounting point to the top of the core it was the same. Mine fortunately did not need a shim.

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Old 06-14-2022, 02:03 PM
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Excellent post in that thread, thank you.

I'm going to have to start from square one and get the frame level and check for errors in the horn ... then progress from there.

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Old 06-15-2022, 06:35 AM
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Quote:
Originally Posted by Formulabruce View Post
Frame horn to datum, or floor, with car on even ( verified) jack stands.
On F bodys the core is shimmed at mounting where it hangs off bottom of frame
Thank you, this ended up the only way I could get consistent results.

(calibrated my digital level with my machinist master level)

Trunk valance was reading dead level .
Roof dead level to 0.1 degree depending on where I placed the level.
3/16" off at door handles (obviously numerous compounding factors)
Core support 1/2"-5/8" off at the fender bolt holes.
Lower cowl fender bolt hole flange ... level

Core support, bumper, radiator ... all that stuff is already installed so couldn't get to the tip of the frame horn. Error at about the point of the sway bar mounts seems negligible .. hard to find an absolute accurate point to measure to.

Now my task is to figure out which side is low or high... the right side is suspect because that's where it received some damage years ago.

I have to back it out of the shop to do some paint work on the quarters ... so I guess I should get that done and put it back on the stands and go from there.

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Old 06-16-2022, 06:17 AM
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Default FACTORY SHIMMING;

It's been discussed before but FWIW;
These cars were never dead level/perfect to begin with so you will notice the factory shim dia, shows multiple shims at the core support. This could be anything from none to 4 right out of the gate. So shimming the core support may be required. Fenders mounted is best for correct gap setting.
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Old 06-16-2022, 06:38 AM
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I'm having to step away from it every now and then or I get to obsessed with one gap or another. It's a driver .. first pot hole I hit will probably rearrange things

I'm guessing the factory was more concerned about things like door to fender gap rather than how level the front is? I mean people can't see 1/4" out of level, they can see a wonky door/fender gap.

Right now it's looking pretty good, got the fenders on last night ... only problem area is the rear lower corners ... where it's got the typical rust repair patch panel, that's going to have to be tweaked rather than shimmed.

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Old 06-16-2022, 08:18 AM
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Level is ok for hanging a mirror on the wall but for car alignment a bit off wont hurt. I have a good flat garage floor and use that as a 'datum' for taking measurements, thus the comment about keeping things in plane. A bit of a tweak one way or another may be needed to make things just right. Also, the gaps and alignment were ok, but not perfect. You see a lot of show cars that are better than perfect but keep in mind guys will go long out of their way to tweak, weld in excess material etc. during the body building stage to make things work out the way they do. Nothing wrong with that but most cars are not done to that level. Keep the end use in mind, dont sweat the small stuff and get the car on the road and start enjoying it

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Old 06-16-2022, 01:58 PM
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That's what I keep telling myself ... and what my wife keeps telling me when she has to listen to me complain about gaps
My original goal ... to have the car better than the day I bought it in 1976 ... and it's already exceeded that goal.

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Old 06-17-2022, 07:05 AM
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Got the core support pretty much dead level with the rest of the car. Had to add four shims (used body support washers) under the frame to bring it down about 1/2". Measured the tip of the frame horn ... bent up 1/2", doesn't seem to extend as far back as the sway bar mounts so hopefully doesn't effect the wheel alignment ... drove it for years afterward and never noticed any problems.

Might make bumper alignment a pain.

Everything is looking passable, not "show car" gaps for sure, but nothing you can stick a finger in either

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Old 06-17-2022, 08:18 AM
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Old 06-18-2022, 09:08 AM
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Might have to notch the bumper brackets to get them lower if it doesn't have enough travel

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