Extreme Mopars

ExtremeMopars has Mopar, Chrysler,  Dodge,Plymouth  cars & Trucks, Classic & Muscle cars

Mopar,Chrysler,Plymouth,Dodge car & truck information

ChryslerDodge & Plymouth unit bodied cars


The featured unibody type construction is one in which the body shell and the under-body(frame)are welded together into one unit.

To achieve greater rigidity and overall strength of the body-shell,two additional heavy-duty cross members,one under the rear seat area and the other at the extreme rear end of the body are welded to the box side rails.

Heavy duty roof bows are used providing greater strength to the roof panel.

The front door hinge pillar is one continuous piece from the roof rail to the body sill.

Sheet metal seams overlap for improved sealing.         Metal cages, welded to the outside of the cowl side panels, enclose the retaining nuts for attaching fenders and hood hinge supports.

Inner hinge reinforcements assure door alignment and maintain proper door adjustment.

The radiator support, fender wheel housings and cowl panels are attached to the body, adding structural strength to the fore-structure and the body.

Different frame structures are used in many vehicles today

Listed below are the frame structures used in cars as well as trucks. Many are still used today.

Unitized (Unibody ) commonly used today.

Unitized Frame with bolt on subframe structure

Perimeter Frame

X-Section Frame

Ladder Frame

Platform Frame

Frame rails of a 1968 Dodge Charger

Perimeter Frame still used on Pickup Trucks and Vans

Roof "Bows" in this 1968 Charger help to give it more durability.

Trying to assess how much damage has occurred to your unibody vehicle?

Certain parts of the unibody were designed to distort or collapse in order to absorb the energy from a collision. 
Rust being an apparent problem with most old classic Mopars, rust damage can be difficult to assess.
 Rust can easily be hiding under paint or body filler. Look for paint bubbles, this can be a sure sign of rust. 
Especially under or around trim components.
In order to really get a good assessment, removing parts from the car will be a must do.
Crawl under the vehicle with a flashlight and scrape away any dirt, mud or debris to get a good look at any damage that may have occurred from a collision or rust. 
While under the car, probe with an awl to check for rust damage.
If the rust damage is severe, the scratch awl will pierce right through the frame rails.   
When rust is found in the seams, folds, and sharp edges the repairs will be difficult to fix.
No matter if its a Ford, Chevy, or Chrysler these cars were never made to be taken apart.
When severe damage is found, it will be labor intensive to fix. And if you're having the work done by a body shop it's going to be expensive.  

Uni-body Construction for Dodge as well as Today's Modern Rides

For now we will only focus on the unibody since most of the old Mopars were unibody designed.

Unibody construction is the most common use today for modern passenger cars constructed today. When one speaks of a unibody construction vehicle, the floor pans, trunk pans, rocker panels, front cowl, inner fender panels, side pillars, firewall, and roof all help form an integrated structure which carries all the loads and to which the engine and suspension parts are bolted.


Even where the engine and suspension components bolt on to, are made of bent sheet metal and are part of the overall structure.

In the case of my 1968 Dodge Charger by it having the severely rusted out floor and trunk pans, this does affect the integrity of the car as a whole. 

Everything except the drive-train, doors, hood and trunk lid is a stressed load-bearing panel.


Damage to one part of the structure often means misalignment in other adjacent parts, and straightening the bent structure is both difficult and critically important when repairing crash, damage.

When You decide to Restore a Unibody Car, Keep some of these important things in mind

When you are restoring  a unibody vehicle, there are some things to keep in mind.

If your vehicle has been in a serious accident, it will be a lot more difficult to repair.

And if your car is like my 1968 dodge charger, rust can be more of a problem.

Since the structural  integrity is made up of body panels that must be cut out, instead of simply bolting on a new part.