Can the tork cause cracking in the paint

[70chall440]

 

[Kevin71]

I just thought of something else that may contribute to the flexing.  I have replaced all of the bushings and motor mounts with polyurethane bushings.  There is less give in those spots would I guess transfer more twist the rest of the car. 

[BIGSHCLUNK]

I could accept the area on the quarter panel is caused by flexing but the area in the back center of the roof,

I must add I was a bit perplexed by the roof myself............. 

[Grec]

When I was a teenager, my dad had a friend that was a Mopar nut. The guy, literally, had the pieces to build two or three 71 Cudas in his basement. I distinctly remember multiple real-deal Shaker setups, full interiors, gilled fenders, grills, etc. This was in the late 80s-early 90s before prices went nuts.

Anyway... I remember him talking about a friends' Road Runner at one point, with the aim of impressing upon me the power that BB Mopar's had. Said he took it out for a run after getting the Hemi (maybe 440?) built up and a stout Dana w/ slicks. Supposedly the thing grabbed so hard that it put a crease in the roof.

I have no reason to doubt the story. :-)

[70chall440]

If he dented the roof he had some serious issues with structural integrity of the car. Look at all of the racers, how many creased roofs have you seen? The way a unibody is constructed, creasing a roof would result in a lot of other issues such as broken glass, doors that would not open/close, etc. Not saying it is impossible, but I would have to see it to believe it.

[jimynick]

Most of the guys running their cars that hard also had a cage in them. I've personally seen a 67 Nova SS 2dr h/t 327-350hp 4 spd car that bent the body so much that the doors wouldn't close properly any more- and didn't break any glass, either. I'm not saying that story is true, but if you put a stout hemi or BB in a stick shifted, slick equipped car, with a Dana that would take the abuse and couple that to a wildman behind the wheel- well, then things can happen. Who knows? The point of this thread, is to try to figure out what happened to our fellow member's car. I think we'd all agree that stiffening the car up surely won't make matters worse, eh? 

[BIGSHCLUNK]

Most of - and didn't break any glass, either.

I must add we've had lots of wrecks come in that glass was severely "bent" but not broken. Sorry I dont have a pic of this,  but some glass will 'bend" quite a bit before shattering.

[70chall440]

regardless of all of the comments about the possibilities; I agree that we all agree the car should be stiffened up and most agree that the side cracks are at least in part due to poor prep underneath.

Stiffen it up, see if you have someone (or do it yourself) possibly patch the damaged areas and blend them in to see if you can correct it and ensure it isn't having other issues.

[rhamson]

I agree with you to a certain point. I have had two Challengers that have had cracks in the quarter panel to roof area where the rear window meets. This is IMO because the weld is the cause of the failure. The manufacturer only spot welded a tab behind and below the window line. I went back and welded the two together so there is no question of flexing. The more I think about where these two areas have failed on the questioners car is because of poor prep. Here is a picture of where I am talking about.

[YellowThumper]

I agree with you to a certain point. I have had two Challengers that have had cracks in the quarter panel to roof area where the rear window meets. This is IMO because the weld is the cause of the failure. The manufacturer only spot welded a tab behind and below the window line. I went back and welded the two together so there is no question of flexing. The more I think about where these two areas have failed on the questioners car is because of poor prep. Here is a picture of where I am talking about.

My 74 has cracks just like that. All original and a small block. Factory weak point. As for the roof my guess is improper previous fix.

[rhamson]

My 74 has cracks just like that. All original and a small block. Factory weak point. As for the roof my guess is improper previous fix.

I have seen the same cracks on other cars as well. If you look at my of my current car you can see that the original body guy before me just filled it and the seam with bondo. I think it was a vinyl roof which I have heard was the standard practice from the factory. This car came without a vinyl roof when I got it. I went back and leaded the seam in so it will not shrink again.

[CHL2T]

I have seen the same cracks on other cars as well. If you look at my of my current car you can see that the original body guy before me just filled it and the seam with bondo. I think it was a vinyl roof which I have heard was the standard practice from the factory. This car came without a vinyl roof when I got it. I went back and leaded the seam in so it will not shrink again.

Same deal on my 70 318 Challenger. When I close the door and put a finger there I can feel the flex.....