Those who ignore history are destined to live happy lives (or something like that…)
From when I owned Cora before, I knew some of the car’s history, just by having to work on it. But some of it I had to research. Unlike a lot of other marques, Corvettes can be somewhat unique, car to car. This is partly due to the small volume runs (in comparison to other GM models), the isolated design team for Corvettes (at least in the 70’s), and the tendency for Rolling Model Changes (RMC’s) to occur on the assembly line anytime during a given model year.
For example, in Cora’s case, I knew from periodic maintenance that something strange was going on with the upper and lower radiator hoses (Cora’s original radiator used a “1977” upper radiator hose and a “1976” lower radiator hose).
In 1976, GM only expected to make 35,000 Corvettes, but when dealers ran out of Corvettes 2/3rd’s of the way into the year, it was obvious that GM would have to expand the production volume for the ’76 model (in the end, 46,558 1976 Corvettes were made). The problem was that the factory and design teams were in the process of switching over to the ’77 model that had several design change differences with the ’76 model. Cora’s production date and serial number are a little over 10 cars into this “new” ’76 model production run.
A little aside is necessary here; when an OEM (such as GM) builds a car, they depend on a number of Tier-1 manufacturers to supply the necessary parts. Generally, apart from the chassis (fiberglass and frame), engine, and transmission, the rest of the parts come from Tier-1’s and GM assembles them into a final car. So to meet the OEM’s delivery dates (and avoid an assembly line going down due to lack of parts), the OEM schedules these part deliveries with the Tier-1’s several months in advance (this includes new parts that might be going into a new model year).
So, the scenario here is that the assembly line was getting ready to make the ’77 model Corvette when suddenly the order comes from above that they need to continue making more of the ’76 model (11,000 more as it turned out). But the Tier-1 parts suppliers had already geared up to supply the ’77 model parts (where they were different) and did not have production scheduled for ’76 model parts.
So how did they handle this situation? I think the assembly line started being creative. When the 1976 parts ran out, they started using 1977 parts (where they fit without any issues). When the parts did not directly fit, they hand modified some of them to make them fit. Other part changes they were managing during the change-over were:
- A “Pancake A/C Compressor” was introduced
(Cora has the Early Long A6 A/C Compressor)
- The Rear Bumper Corvette Trim was changed from 6″ to 8″
(Cora has the Late 8″ Emblem)
- Interior Components were changed – larger Radio, T-Top brace Dome Light added
(Cora has the Early Interior without the Dome Light and larger Radio)
So in the case of Cora’s radiator hoses, I think they modified the upper radiator outlet to work with the 1977 upper radiator hoses that they had plenty of. It took me a number of trips to the auto parts store to get this scenario worked out. I kept coming home with matched sets of hoses, one set for ’76 (where the upper hose wouldn’t fit) and then one set for ’77 (where the lower hose wouldn’t fit).
Nowadays, the auto parts vendors do recognize that there are some part differences between “Early” ’76 and “Late” ’76, but even then there are problems. The “Late” ’76 radiators and hoses are really just the ’77 configuration (i.e. not a mix of ’76 and ’77 hoses on the same car). It seems Cora was somewhat unique in this regard. As for how many ’76 Corvettes are like Cora (with different upper and lower hoses), I have no idea. Perhaps some other ‘Vette owners can chime in here…do you have a ’76 serial number 35,0xx car with different upper and lower hoses? I’d like to know…leave a comment.