Fiberglass panel process

This is My process to make MY custom rear body panel and bumpers.  

My goal was to make a rear panel for the 1974 through 1982 Corvette that would be as similar as possible to the earlier C3 Corvette that used steel bumpers and had that super cool swoop at the rear.  

I started by obtaining a good rear clip from a 1971 Convertible from a shop in Grand Rapids Mich.  It has a rusted frame but the body was in good shape.

First step, acquire 1971 rear clip from Grand Rapids Mich

 

After removing the body from the frame I went over the area that I wanted to make a mold from and put a few coats of paint on it and wet sanded to highlight imperfections.  Then began to measure the body to document the correct location for the body panel when finished.

Measuring overall dimensions

Measurement from gas door to end of body

Straight back body line, no flare

At this point I checked against the body of the target vehicle, a 1976 Corvette.  There are many subtle differences!

1976 left rear quarter, showing hour glass taper

While working on making a mold from the 1971 rear clip, we acquired the next vehicle; a 1974 Convertible.  This car has a perfect body and will be used to build a proto-type rear panel.  Blending the part taken from the mold of the 71 with the body of the 74 will require extensive modification of the area that the panel attaches to at the lower portion of the quarter panels.  

Acquire 1974 Convertible as a development test bed from Ft Worth Texas

In fitting the first panel to the car, modifications are made at the lower quarter panels and all along the sides of the panel to blend in with the taper of the body on the 74 and later bodies.  The pre 74 car quarter panels go straight back as seen in the photo above, so some creativity was required to make a smooth transition. 

First part from mold being test fit and minor modifications made

The newer body places the body side light higher up in the panel than where it is in the earlier car.  The chrome bumpers would extend over the lamps but in the later car, the chrome bumper would block out the light.  Also, the width of the body is slightly different in that area so modifications are made to the bumper.

Fitting custom bumpers painted in red for visibility in the photo

My custom bumpers are modified to duplicate the original look but are slightly shorter along the side of the car, stopping before they cover the side lamp.  They were molds taken from the original bumpers of the doner 71 rear clip.  I also provide inner steel frame inserts that bolt to the frame of the car via brackets, like the originals did and then the bumpers are glued to the steel brackets.

Steel frame inserts into the figerglass rear bumpers

I provide steel brackets that also then bolt the bumper brackets to the frame as seen from under the car in this photo…

Proto-type brackets to bolt bumper to the frame of the car

A final fitting is done to the panel, cuts made for exhaust and tail lights, ect.  I suggest mounting the lights prior to installing the panel and building a simple wire harness to attach to your existing wiring loom.  The panel is shown in base coat, prior to clear coat after final fit check.

Panel is base coat with checking fit on the target car; 1976 Stingray

The lights are installed along with wiring and then mounted to the car.  Bumpers attached, lic plate frame etc.  Note the way the bumper stops before it cover the lamp on the quarter panel.

panel installed with lights and bumpers.

Dimensions are now double checked to show that the panel does NOT extend the car back farther, and it is NOT higher or wider.  It is as close to the original pre 74 body as possible, considering the small modifications made at the bottom of the quarter panels.

     Aprox 16 3/4 inches

Verification of dimensions

Here is a side by side comparison of  another early C3 at Gateway Classic Cars in O’Fallen ILL.  The measurements are Identical and it’s hard to tell that the 76 is not an earlier car unless you check the vents and front end of the 76

                                Sample car at GateWay Classics,                                         measurements confirmed, matches my panels!

 

My panel does not extend further back than the original early car.

Here at two images of the same car, but one has been photo shopped to show what it would look like if you glassed in the panel.  I deliberately made the panel so that it could be bolted on with no modifications to the car.  That way you can always remove it for what ever reason you choose and put the car back to original condition.

 

 

First proto-type panel and bumpers on the 76

panel blended in, photoshop

My kit comes with the panel, two bumpers (with steel insert brackets) 6 mounting brackets, panel fasteners and indepth instructions.