Increasing rear tire clearance in a '70 Charger.

[Kern Dog]

Hello again!
Like many of you, I wanted to fit the widest tires that I could in my car. When my Charger was toward the end of bodywork and paint in 2003, I measured carefully and ordered tires and wheels that allowed free movement without rubbing the outer body.

The look that I wanted for this car was a sort of NASCAR-esque appearance where the body was laid over the widest tires I could fit and afford.
The goal was to look sort of like these cars:

Aside from the larger diameter wheels, I think the wide tire look was met.

 

[Kern Dog]

The front tires clear just fine. I have 18 x 9 Intro Twisted Vista wheels with 4 3/4" backspacing. The front tires are a 275-40-18 Nitto NT-05. The front don't rub the outer body but do rub the frame rails at full left and right.

The rears are 18 x 10 with 4 3/4" BS and a 295-45-10 Nitto NT-05 tire. They clear most of the time....

They never make contact with the outer body. Where they do make contact is in a spot that I didn't notice when I measured so carefully.
The 68-70 Chargers have a strange design shape for the outer wheel house. I suspect that the 66-70 B body models all have the same problem. In the old days, a man would just install air shocks and be happy with that.

It is easy to see with the quarter panel off the car.

Instead of the tub following the quarter panel straight up from the wheel opening, it goes up at about a 45 degree angle to this strange ridge.....

 

[Kern Dog]

My plan is to modify the outer "tub" to closer match the outer body...

I did the "photoshop" before I found the actual picture of what that shop did to the tub:

Nice difference, huh?

My mods won't be as extensive as in those photos for a few reasons. First off, I'm not going to be removing the quarter panels to do this. You can see that the roof structure support had to be cut to make room for the new outer tub.

 

[Kern Dog]

From the wheel side, you can see the point of contact the tire has made.

As it is now, I can't drive with a full tank and a passenger without the tires hitting the tubs when I hit a bump. I have Mopar Performance 440/Hemi leaf springs, Bilstein shocks and a 3/4" sway bar so it isn't as if I'm riding on 52 year old springs. I have about 2 1/4" of clearance without me in the car. After these modifications are done, I should actually be able to hit the bumpstops before the tires make contact anywhere.
Last Spring, I modified the outer tubs in my other '70 Charger. The gains that I was able to make there are great and while they would also work on this car, I want to try something different.

These next pictures are of my other Charger that I call Jigsaw.
I scraped the undercoating from the work area. Here you can see the ridge of the tub and how it intrudes into the tire space.

 

[BeepBeepRR]

My plan is to modify the outer "tub" to closer match the outer body...

View attachment 1235846

I did the "photoshop" before I found the actual picture of what that shop did to the tub:

View attachment 1235847 View attachment 1235848

Nice difference, huh?

My mods won't be as extensive as in those photos for a few reasons. First off, I'm not doing removing the quarter panels to do this. You can see that the roof structure support had to be cut to make room for the new outer tub.

With that modification it sure helps not to have to do a leaf spring relocation. Or did you do that too? I also believe the passenger side axle on all mopars is further out. You can verify this by measuring both sides. The rearends are just a little more to the right side. Found this to be the issue on my friends GTX I didn't believe it at first then went and measured the Road Runner. Sure as **** passenger side is further out. The chargers you posted pictures of I'm sure you can see that the quarters are widened.

 

[Kern Dog]

On the Jigsaw car, I cut along the ridge line and also made cuts perpendicular, then pushed all the flaps toward the quarter panel.

With that ridge now essentially Inverted, I welded up the seams.

Next was seam sealer in case there were any pinholes, then undercoating.

 

[Kern Dog]

With that modification it sure helps not to have to do a leaf spring relocation. Or did you do that too? I also believe the passenger side axle on all mopars is further out. You can verify this by measuring both sides. The rearends are just a little more to the right side. Found this to be the issue on my friends GTX I didn't believe it at first then went and measured the Road Runner. Sure as **** passenger side is further out.

The chassis is stock, no spring modifications on either of my cars.
Your comment about the axle housing offset has me curious. I'll have to check on that tomorrow.

 

[Kern Dog]

The wheel tub work in Jigsaw is a big improvement over the stock shape but the result was still sort of like this:

For the red car that I call "Ginger", I want the tub to closer match the outer body instead of going up at an angle.

This will leave adequate room in case I ever want to use wider wheels and tires in the future. Even if I don't, I want clearance so that if I want to have 4 people and a full tank of gas in the car, I'll clear just fine.

 

[BeepBeepRR]

My buddy bought new tires for his GTX wider than what he previously had on it. I don't remember the actual size. But the driver side was fine after he drove 2 miles to his house. The passenger side tire was mangled from the lip on the wheel house and quarter.

 

[Kern Dog]

The work on the Jigsaw car was done with no fear of damaging nice paint because.....

....the car does not have nice paint!

With Ginger, I have to be more careful. Since I want the wheel tubs to sit out wider, I am looking at welding near the back side of finished paint. I'd blow a gasket if I burned the paint and had to repaint the car. GOOD luck matching paint on a 19 year old paint job, this would mean a FULL repaint.

What I am considering is using a panel-bond adhesive. This stuff is supposed to deliver a connection that is as strong as a weld and is also corrosion resistant.
I plan to dig in and get to work this weekend. As usual, I'll tell the story with lots of pictures and my usual attention to detail. My Dad used to say....."When a man asks you what time it is, you tell him how to build a watch".
Yeah, sometimes Dad was right.

 

[BeepBeepRR]

The best phrase I got from my Dad was be like Pop not like Sis lift the lid when you piss..

Just so happen to be watching this video from our resident Birdsong..

 

[Kern Dog]

I didn’t click on that but I may have already seen it. He does great work.
It has been several years since I first planned on doing this. I’d have to check my notebooks but I suspect that it has been at least 8-10 years. So many other things got in the way. Now that I’m driving this car more with the 5 speed swap, I’m anxious to keep refining the car to make it a better street car.

 

[Boris7K]

Thanks for posting this, I was trying to figure out how to fit 295s on my Coronet. My paint is original I believe so I'll have to see what kind of room there is for welding.

 

[F4R/T]

KD I would personally not use panel bond, most glues have a life of 7-10 years of use, while they don’t let go it’s not a weld.. I do understand , that was from a paint rep years ago. I’m just sharing what I know/ have heard.
All those jumped chargers make me cringe even if they say they aren’t restorable.. look what we fix now .. Good Luck and I like the wide nascar look.

 

[BeepBeepRR]

Hey Kern.. Here is a topic about the rear ends being offset to one side. This holds true to later model cars too its not just a 66/67 issue. My friends 69 Roadrunner and the 70 GTX are the same.

https://www.forbbodiesonly.com/moparforum/threads/67-coronet-rear-wheel-to-lip-clearance.234734/

 

[BeepBeepRR]

Made this video today. It will be a minute before its online.

 

[Kern Dog]

Hey Kern.. Here is a topic about the rear ends being offset to one side. This holds true to later model cars too its not just a 66/67 issue. My friends 69 Roadrunner and the 70 GTX are the same.

https://www.forbbodiesonly.com/moparforum/threads/67-coronet-rear-wheel-to-lip-clearance.234734/

I checked mine. I am within 1/8" by checking the axle itself. I am dead even from the axle to the wheel lip but 1/8" further out from the inner wheel tub on the right side. Plenty of variables that can screw with the numbers though. I also think that my right quarter panel was replaced some time before I bought the car. There was some history of these cars having variances from side to side and front to back in terms of panel gaps, ride heights, etc.

 

[Kern Dog]

Once the wheels were off, I started into it. Before cutting anything, I needed to remove the undercoating. It is much easier to remove with the wheelwells intact and rigid. It would be much harder to remove after I made cuts since the metal would be floppy.

Last year when I did these mods to my other car, I read about the various ways to remove undercoating. By far, the needle scaler was the preferred method. This is a needle scaler:

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They are pretty simple in design. Air powered with a small hammer type piston inside that punches at these 1/8" steel rods....

Don't forget the oil...

Also, even if you're not that safety conscious, the following stuff really helps!

The needle scaler is loud so the ear plugs help...plus they keep flying chunks out of your ears! The glasses do help keep your eyes safe.
Ear muffs are overkill but if you have a LOUD compressor....

The muffs might be a good idea.

 

[Kern Dog]

Getting a look at the wheelwells, you can see that the wheelwells are covered in this stuff. The underbody was not though.

You can see where the tires rubbed on the outer tubs:

 

[Kern Dog]

Now, the scraping begins....
The process is simple. Press the lever to activate the scaler and press it against the metal at an angle of about 45 degrees. You can wave the scaler back and forth, you can move it like a leaf rake fore and aft, you can push or pull.

Wait...what is that ??

F 8 green? Yep....that is the original color of this car! Back in 2002 when I decided on a color change, a repaint in Green was never a consideration. Nowadays, I can appreciate a nice green colored car. (No, I am not going back to green)

The pile of chunks was impressive...

The scaling leaves most of the paint behind so to get the metal ready, I used this:

....along with 40 grit discs....

Mountain Dew.....BEST drink ever!

You can see where I tried to make some clearance on that bulge but it wasn't nearly enough.