C4 Corvette Exterior Body Panel Differences Informational Guide
The contents of this page are meant to describe the differences and exchangeability of exterior body panels for the various model years of C4 Corvettes.
Hood information is not included on this page but can be found by clicking here.
Note* For simplicity, at this time Callaway and US Export versions are not covered in this write up.
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The front bumper cover, nose, fascia (however you like to call it) had 2 different styles in C4 Corvettes. 1984 -1990 and 1991-1996. The front license plate filler is not interchangeable between the two different bumper covers. Same goes for the lower black plastic air dams as they changed between the 1984 -1990 and 1991 - 1996 bumper covers.
These front bumper covers are interchangable from the newer to older styles. This is popular for many who wish to update their 1984 -1990 cars with the 91-96 style bumper covers. However in doing so there are a few other items that are necassary to change. Further details on this coming soon.
Some of those who are new to C4 Corvettes may be surprised to find that there where 5 different rear bumper covers over the model years. (5 US versions, there were additional designs for export versions) These were 1984-1990 coupes, 1986-1990 convertibles, 1990 ZR1's, 1991-1996 Coupe and Convertibles, and the 1991-1995 ZR1's.
The 1984-1990 Coupe rear bumper did not have an opening for the third brake light. In 1986 third brake lights were mandated on all vehicles in the US. 1986 - 1990 Coupes had the third brake light mounted on top of the rear hatch and convertible models (which started in 1986) added the brake light in the rear bumper.
The 1991-1996 rear bumpers are the same for coupe and convertible.
While ZR1 Bumper covers appear the same as 1991-1996 bumper covers, they are wider than standard coupes due to the increased width of quarter panels for the ZR1 models. The 1990 model ZR1 used the newer style rear bumper cover with the 84-90 front end styling. For this reason the 1990 rear bumper cover is unique to only 1990 as the middle black molding strip was a bolt on piece in this bumper cover and matched that of the remaining 84-90 style moldings that are on the front end of the car. The 1991-1995 ZR1 bumper covers also received bolt on moldings of the newer style which is unlike the base version 1991-1996 bumper covers which had the molding formed into the cover. In addition all of the ZR1 models retained the roof mounted third brake light and did not have an opening for the third brake light in the rear bumper cover.
The front lower fender panels had three different designs (four if you consider the molding difference on 1984 models) throughout the course of C4's. These year variations are 1984-1990, 1991-1994, and 1995-1996. The fender panels are all of the same dimensions and are easily swapped out. However, applying 1991 and up fender panels to a 1990 or earlier car requires molding and bumper cover changes on the entire car in order to look correct.
The 1984 fender panel is the same as the 1985-1990 fender panels. However the black molding trim (which is removable on the 84-90 fender panels) has "Cross-Fire Injection" printed on it whereas the 85-90 reads "Tuned port Injection"
Both the 1991-1994 and the 1995-1996 fender panels have the center molding trim molded into the part and is not removable like the 84-90 panels.
The Doors on all C4 Corvettes (excluding ZR1's) were the same on the exterior. On the interior there were only minor changes but these can be easily overcome and allow doors to be interchanged throughout most years of C4's.
ZR1 doors appear very similar at first but are totally different than base model versions. The door shells of ZR1 cars were thicker overall to accomadate for the increased width of the ZR1 rear end.
Some of the minor differences of non ZR1 doors are:
1. Doors had different holes drilled at the factory to accommodate the change in window regulator style that occurred in late 1986 early 1987.
2. 1984 and 1985 doors have a heavier metal brace down the middle of the door than the later cars do. Because of this (and differences in glass thickness of these years) the 84 and 85 doors are a fair bit heavier than later doors. Due to this heavier brace, an 84 or 85 door could not be installed on a 93 and newer car with passive keyless entry due to limited room for the receiver antenna.
3. In 1990 the interior of C4's was drastically redesigned. One of the changes moved the front speakers from being mounted within the door to the inside of the rocker panel inside the car. On the 1984-1989 there is a hole cutout for the speaker assembly at the lower front of the door. On 1990 and up doors this section is filled in with a thin fiberglass panel. This panel can be easily cut out if placing a 1990 or later door to a pre 1990 car. Photo below shows an example of a 1993 door with this panel still in place.
3. On 1984-1992 doors there was an alignment pin on the top rear inside edge. This pin aligned to a receiver piece in the door jam. Starting in 1993 this rear alignment pin was no longer applied.
The molding style of C4's changed in 1991 along with the major front and rear bumper changes. The moldings of 1984-1990 were a thin black rubber on all cars where as the 1991-1996 style molding was painted to match the cars exterior color.
Bumper Cover Moldings
On 1984-1990 models the front and rear bumper covers had a molding design which was an additional bolt on item, whereas the 1991-1996 models had this molding incorporated into the mold of the bumper cover and is not a removable piece.
On 1990 ZR1's the rear bumper molding is different than the base model 84-90 cars due to the increased width of ZR1 rear ends. For 1991-1995 ZR1's even though they appread like the incorporated moldings on base models, the rear bumper cover had removable molding pieces.
Door moldings are a removable piece for both the 84-90 and 91-96. The later style moldings can be applied to 84-90 doors as a simple bolt on change.
Fender Panel Molding
On 1984-1990 fender panels the molding is an additional bolt on item similar as to the bumper covers of the same model years. The 1991-1996 fender panels have the molding incorporated into the mold of the panel itself and is not removable. The black molding trim on 1984 models has "Cross-Fire Injection" printed on it whereas the 85-90 reads "Tuned port Injection"
Quarter Panel Moldings
The small strip of molding on the quarter panel in front of the rear tire is a bolted on piece on all C4's. The later style 91-96 moldings can be simply bolted onto the 84-90 cars. Note* The quarter panel molding pieces of ZR1's are slightly different than the base model version. These ZR1 specific moldings are slightly shorter and have bolt holes that are closer together than the base version.
The rear hatch glass from 1984-1996 models can be interchanged without issue. However the upper metal hinge of the rear hatch had differences due to application of 3rd brake lights. 1986-1990 Coupes and all ZR1 models have third brake lights mounted on the upper hinge plate while 1984, 1985, and 1991-1996 do not have the 3rd brake light applied. The hinge plates can be carefully removed and swapped to other glass if needed.
The rear hatch lift struts are able to be applied 1984-1996. The 1984 lift struts are longer though than the 1985-1996 struts, and therefore raise the rear hatch higher than later years. GM shortened the length of the struts in 1985 in order for people to reach the top of the hatch more easily for closing it.
Coups and Convertible models had different styles of gas door lids. The difference can be noticed along the top edge of the lid in the below two photos. While door lids are not interchangeable between coupes and convertibles, they are able to be exchanged throughout all model years. That is, 1984-1996 for Coupes, and 1986-1996 for Convertibles. (Not considering differences in emblem designs)
For further information on replacement items for your C4 corvette please feel free to give us a call or contact us at email@example.com.