[Chassis Restoration]

Corvette Grand Sport #002

The "heart" of the Grand Sport is the frame. It carries the factory- stamped serial number that defines its unique existence.

The philosophy behind the restoration & preservation of Grand Sport #002 dictated that those parts most susceptible to vintage racing damage (the original body, interior and engine) would be preserved, but the frame would be carefully documented, restored and used.

A great deal of time and effort was spent on documenting the existing condition before repair and restoration began.

Constructor's and inspector's marks were recorded and incorporated as part of the documentation of the car. The evidence of the craft is an important part of the legend of the hand-built Grand Sports. On the other hand, common, latter-day repairs are not necessarily preserved.

With an eye toward vintage racing, careful assessment of structural soundness is also important. Modern safety enhancements are also incorporated wherever possible.

[Courtesy: GM Archives]
Grand Sport Chassis - GM Engineering Shop (circa 1962)

Disassembly & Documentation

Since it had been decided to preserve the original, unrestored body, it was carefully lifted and separated from the chassis. Once all of the fittings, such as seats, steering column, etc., are removed, only eight fasteners actually attach the body to the frame.


Chassis - Picture 1


Chassis - Picture 2

This was the first time since the 1960's that the body had been separated from the frame, and close attention was paid to all of the details that became visible.

Here we see a body mounting point that still has the black tape used by the factory to hold the body shims in place.

This picture shows the gas tank insulation material which was glued to the frame. Note the red grease pencil mark around it.


Chassis - Picture 3


Chassis - Picture 4

The bare frame after being washed with soap & water. A mild solution was used so that no inspection or construction marks would be removed.

After the paint overspray and years of dirt & grease were removed, the frame was found to be in excellent shape, with only minor dents & scrapes.

After washing carefully, the steering link was revealed to have factory yellow inspection paint at each rod end.


Chassis - Picture 5


Chassis - Picture 6

Close-up pictures were taken of all areas to document all bolts and fasteners, etc.
As the paint was stripped on the upper control arm, yellow inspection marks appeared at each end of the forging.


Chassis - Picture 7


Chassis - Picture 8

As the paint was stripped on the driveshaft, a stenciled number partially appeared. According to research, this number should be "3831753".
After cleaning, the driveshaft front yoke shows the original lime green inspection mark.


Chassis - Picture 9


Chassis - Picture 10

View of frame after plastic media blasting.

Plastic media was chosen to clean the frame as it causes minimal damage to the base metal surface. It also allows for inspection of the various layers of paint as they are removed.

During this process, it was noted that the factory had applied red oxide primer under the original high gloss black finish coat. Note also that the right side frame tube has a black phosphate finish, while the balance of the frame is a brighter mill finish steel tube.

Right side frame tube has evidence of where original battery box was attached (pre-1964 configuration).


Chassis - Picture 11


Chassis - Picture 12

Large dents in the frame, such as those pictured here, are to be repaired.

Repair & Refurbish


Chassis - Picture 13

Frame after spraying with correct red primer as original. The primer will keep the frame from rusting while major dents are fixed.
A flat plate had been crudely welded to the left side frame tube. Since neither of the former mechanics (Bill Scott or Bill Mayberry) recalled doing this repair, the area was cut open to investigate. It appears that the frame tube was damaged and just had a quick fix made.


Chassis - Picture 14


Chassis - Picture 15

The same area after being repaired.
While cleaning the frame it was noted that all other round frame end plates had a centerpunch mark & 2 scribe lines from when they were originally fabricated.

These details were recreated on the repaired area.


Chassis - Picture 16


Chassis - Picture 17

View of frame after all major dents were repaired. Minor dents and scratches were left as "patina".
Top view of frame after painting with high gloss black finish as original.


Chassis - Picture 18


Chassis - Picture 19

Bottom of restored frame.
Research indicates that the rear spring (shown here) was added to the car by GM in the '63/'64 period. It is a 7-leaf F40 option type, and it was used without the normal liners.


Chassis - Picture 20


Chassis - Picture 21

The spring has this unusual number stamped on the end of the bottom leaf.
The 7-leaf rear spring was re-painted gray as was original when GM re-worked the Grand Sports for Nassau in late 1963.


Chassis - Picture 22


Chassis - Picture 23

Halfshafts restored with the correct stenciled numbers, hand-written weights, inspection paint marks & u-joints without zerk fittings.
After crack testing and cleaning, the front suspension components were electro-less nickle plated as done originally by GM.


Chassis - Picture 24


Chassis - Picture 25

Newly manufactured stub axles for the Halibrand knock-off wheels. Two complete sets, exactly like the originals.
Inspection of the original front aluminum Girling calipers indicated that the brake fluid was leaking past the seals due to corrosion in the seal groove area. The affected caliper halves were re-machined to correct this problem.


Chassis - Picture 26


Chassis - Picture 27

G.S. #002 had two different types of front brake calipers factory installed. The 1st generation was the cast iron Girling calipers for the original solid rotor system. The 2nd generation was a combination of aluminum Girling caliper halves with widened GM cast iron bridges for the improved vented rotor system.

The 2nd generation front calipers are shown here, fully restored, with the corrrect fasteners, date codes, inspection marks, stainless steel pistons & quick release pads.

G.S. #002 had only one type of rear brake caliper factory installed. They were cast iron Girling calipers used with original solid rotors. The calipers are shown here, fully restored, with the correctly plated finish, date codes, stainless steel pistons & quick release pads.


Chassis - Picture 28


Chassis - Picture 29

Restored right rear suspension with solid rotor, cast iron Girling caliper, quick change pads and gray F40 shock.
New clutch linkage bellcrank to replace original (which was changed when Penske installed the 427 drivetrain).

Note the special "lightening" holes drilled into the arms.


Chassis - Picture 30


Chassis - Picture 31

In an extreme example of how important weight savings was to Zora Duntov & his designers, the Grand Sport used rear alignment shims that were similar to production Corvette shims, except that they were lightened with stamped holes.

Fortunately, there was one original alignment shim pack still on the car. It was used as a pattern to reproduce the rest of the special lightweight shims for the other trailing arm.

The original Grand Sport fuel tank was made of polyester fiberglass. For safety reasons, it was decided to produce a new exact duplicate fuel tank that could incorporate a modern fuel cell bladder.

A plaster mold was taken of the original tank as seen here.


Chassis - Picture 32


Chassis - Picture 33

Top & bottom halves of the new fuel tank mold.
New fiberglass Grand Sport gas tank halves.


Chassis - Picture 34


Chassis - Picture 35

The top half of the gas tank shell after laying up the Kevlar material inside for puncture resistance. New filler neck parts were custom made to duplicate the original filler neck but with a "rollover" check valve and fuel cell nut plate fitted.
The new fuel tank filler neck with rollover check valve looks stock from the outside.


Chassis - Picture 36


Chassis - Picture 37

New aluminum radiator support assembly, fabricated to original specifications, is approximately 1/4th the weight of a production Corvette steel radiator support.
A new old stock Harrison oil cooler was installed on the radiator support as was original. Special lines were fabricated to clear the hood and route through the support. These oil lines were fabricated with original "cloth braid cover" rubber hoses, complete with 1963 date codes.


Chassis - Picture 38


Chassis - Picture 39

New exact duplicate body as it is lowered onto the completely restored original chassis.

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