[jarretts70]

1970 GTO. Ridiculously long term project....not sure whether to put this in the body section or suspension...

Quick backstory for context: I got the car eons ago. It had been in a minor fender bender some time in the 70's, stripped of its drivetrain (including the factory discs & rear end) & left for dead . 49xxx original miles. The frame & original floors were beautiful & straight, except for some cracking at the rear shock mounts. I embarked on a body-off rebuild; I've already done a few A & G bodies, so I'm pretty well versed in what's involved. I did have to replace the 1/4's & trunk floor. During the sheet metal work I had the body on & off the frame a couple times and it always bolted together with no issues.

Jump ahead to last year. I sent the frame to a guy who blasted it, boxed the rails & added some gussets to the rear crossmember - he also repaired & braced the rear shock mounts. Then he powder coated it. I put the body back on the frame with all new bushings, everything went perfectly fine. Body bolted down easily, perfect side to side alignment measuring from the rocker pinch weld to the frame. Panel gaps are really good, doors & trunk open & close as they should, etc...Zero indication (to me at least) that there are any issues with the frame..

The car is on blocks placed under the front tires & rear control arms, so the suspension is loaded. All the blocks have been shimmed to be as close to level as I can get. Front tires are a matching pair. I'm in the final body work stages, fitting doors & sheetmetal, which is going very well (except for the known issues with repro front fenders). Full suspension, but no engine/trans, or glass...or interior....

This thing sits about 1 1/2" lower on the drivers side rear than the passenger side. I've tried 2 sets of rear springs - no change. This has me very worried that something went sideway when the frame was boxed.

I would think that if the frame were twisted enough to make the car sit that unlevel it would be so corkscrewed I'd be able to see it with my naked eye....I would think a frame that twisted would put up a fight when trying to bolt the body down. As noted, I had no issues.

Looking for opinions if I need to worry about this now, or should I wait until the car is more completed? Weight of a drivetrain and so on...Usually I don't get too worked up over a cars stance when it's this incomplete, but this is so obliviously wrong I'm debating on taking it to a different frame shop as it is.

[tom s]

Swap the rear coil springs and see if it changes.Tom

[DavesGTO]

Maybe check a few dimensions for piece of mind?




Sent from my iPhone using Tapatalk

[694.1]

Or try the front springs. Really.

[dataway]

I don't know if you have original OEM front springs or not, but they were often asymmetrical with a heavier spring on the right side where the AC is. If these were swapped to the wrong location during reassembly it could cause a problem.

[jarretts70]

All the original springs were long gone, they must have disappeared when the drivetrain was stripped.

It's more of a resto-mod anyway. I started with a set of Hotchkiss 1" drop springs for a 66' Chevelle that a friend donated. He switched to coil-overs before getting his car finished, so these springs are basically new. Because 66' springs aren't pigtailed on both ends I figured that might be my problem, so I bought a correct set of rear springs from Bell Tech - same problem. Switching rear springs side to side has no effect, but I've never switched the front ones. I'll look closer at the front. And I'll use daves frame chart & try get some measurements.

[78w72]

another thing to check is the floor areas where the frame bolts to... ive seen some 2nd gen firebirds that had a lean & turned out to be the floor area where the body mounts attached that had been pushed upwards as if the car was airborn at some point in its life. many of these cars were heavily abused & no telling what previous accidents or abuse may have happened. i could see it just by looking but maybe take some measurements on both sides just to confirm the floor is not damaged.

[jarretts70]

I don't believe the issue is with the floor. The reason I decided to rebuild this gutted shell of a car is because the floors & frame were so clean & straight. Besides a bunch of A- bodies I've also done 2 Firebirds in the last decade, had both of thoise down to the bare body as well, so I know what 78w72 is speaking of. But pretty sure that's not the case here...

[MUSLCAH]

Yup….as noted earlier….pay a frame guy to measure it up. Money well spent . You need a squared up foundation first..

[400 4spd.]

Are the front and rear control arm bushing bolts tight?

[jarretts70]

All the control arm bolts are snug but not torqued. I never do that until the car is more complete & closer to it's final weight.

694.1 might be onto something. I had the front end assembled, but decided to change the upper control arms. So this weekend I blew it apart, figured I could double check that the front springs were in it correctly. Kill two birds with one stone. And it turns out I had one of the front springs not seated correctly in the frame pocket.

I broke my homemade spring compressor, I'll pick up a proper one tomorrow. Finger crossed this solves the problem...if not then the next stop is a frame shop.

[jmt455]

It's probably the front springs.
The OEM left & right spring rates were different to compensate for the weight of the steering gear, AC equipment, etc.
The aftermarket springs might not have the same asymmetrical rates.

Funny to see this today; I recently watched a "Roadkill Garage" episode where Freiburger and Dulcich changes the front springs about 6 times trying to get a T-37 to sit level.

[400 4spd.]

Ride height situations with customer cars has caused me to by a tester for

confirming coil spring rates. You can buy them from Speedway.

I was recently able to help a customer with some serious problems on a '53 GMC pick up that he bought and didn't like to drive.

[jarretts70]

Making progress!

Tonight I got the passenger side front spring installed, double & triple checked it's correctly seated both in the frame and the LCA. I also put the Bell Tech rear springs back in it (the correct ones with pigtails on each end).

Vastly improved. A quick measure shows within 1/2" from side to side. Oddly, now the drivers side is 1/2 higher? Goes to show how badly jacked it was due to a simple spring installation error....Tomorrow I hope to have time to pull apart the drivers side front. I'm pretty sure now that I can get it sitting correctly & have a lot more confidence the frame is not a corkscrew.

I'll post the results when I'm finished - thanks to all!

[jarretts70]

Both sides of the front pulled apart & springs checked. Drivers side was OK, just the passenger side was wrong. Installed UMI upper control arms at the same time. It's about the same as yesterday, within 1/2" of level. Considering it's only 1/2 a car (well...maybe 1/3 a car...) I'm happy & confident the fame is ok. Onto the next project - anyone ever straighten a bent Endura bumper for a 1970 GTO ?? Time to start a new thread!

[dataway]

Remember, you load it up with battery, AC components, spare tire etc it can make a difference. And if it's 1/2" high on the driver side ... that will probably go away when you sit in it

[MUSLCAH]

Tire pressure too. Make sure the tire sizes are the same in the front.