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Cameo Ivory 1967
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These cars flexed like crazy. All that torque has to get dispersed.

In the 80's when the IROC craze hit and T-Tops were the big thing, if you looked, most of those cars only had 305's. They werent available with T-tops, 350's, and manual transmissions, unless you special ordered and signed a waiver.

My 79 Trans am with the olds 403, had a crease on the roof, between the Ttops.

What you have there is simply a stress crack. Unavoidable unless you use flex additive. This is why it costs $20k to paint a vette.
 

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I can't find the reference right now, but have read where the area underneath the joint was reinforced during the bodywork phase.
 

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Hi sameold1,

I believe the reference O52 mentions is enclosed.
Restoring my 1968 Convertible-Voodoo II

As previously mentioned, the factory lead filled that area and due to body flex it event cracked over time. My car has done the same even after being properly OEM prepped before repainting. I did not weld that area like the attached post states so I can’t say if that would remedy the problem.

Looking at 68/69 convertibles entered in the GTOAA concourse class you’ll notice many/ most, if driven, have the hairline cracks you reference.
 

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Some fixes noted in threads below in addition to the one in post 7. It's not a Pontiac problem. All the GM A body convertibles had the same issue.



 

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Discussion Starter · #13 · (Edited)
47K miles on this car and it's untouched, body bushings, motor and trans rear even ujoints original to car . Core support was rebuilt during paint and body work. Well I will head out to the body shop and see what happens. No cracks before it went to paint at all..
 

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These cars flexed like crazy. All that torque has to get dispersed.

In the 80's when the IROC craze hit and T-Tops were the big thing, if you looked, most of those cars only had 305's. They werent available with T-tops, 350's, and manual transmissions, unless you special ordered and signed a waiver.

My 79 Trans am with the olds 403, had a crease on the roof, between the Ttops.

What you have there is simply a stress crack. Unavoidable unless you use flex additive. This is why it costs $20k to paint a vette.
1st new car I ever ordered was a 84 mustang GT black on black T tops, 1st rain storm filled the dome light till water was pouring into the interior till soaked, shorted out all the interior lights. Took it back to the dealer 5 times and they never got it sealed right, that was just one of the problems with that F ing ford, last one I ever owned.
 

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Those look like they're in the joints between the quarter panel and the filler panel "above" the deck lid. The factory used a flexible seam sealer there and painted over it. That area will flex some, even on a hardtop but more so on a convertible. If whoever painted it tried to "hide" those joints with body filler (which doesn't flex at at), that's probably why they cracked.

Bear
 

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I will suggest a seam sealer but I will also let him know I want picture of the repair .
Also, on factory original cars those joints are clearly visible, not hidden. They look like a 'trough" that's been filled with just barely enough sealer to prevent leaks.
The paint job on my car is now 11 years old, and here's how it looks in that area:
Hood Automotive tire Bumper Wood Vehicle door
 
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