My Blueprint for a 2011 Corvette C3
In September of 1967, the first C3 Corvette rolled off the St.
Louis assembly line. Yes, it has been 44 years since these cars were
welcomed into GM showrooms across North America. C3 Corvettes were an
instant hit in late September of 1967 and continue to ‘turn heads’ 44 years later. I think
these cars will ‘turn heads’ for many years to come. Why are these cars so
popular and so desirable today? I believe there are several factors.
I think the styling and the sleek look of the C3 Corvettes are the major
factors. If you asked someone to draw or describe a Corvette for you, I
think the majority of car enthusiasts would paint you the image of the ‘shark’
series. Another factor that makes these cars so popular is the
affordability. C3 Corvettes are available to fit anyone’s budget.
Parts for these cars are abundantly available.
There are basically two types of Corvette enthusiasts: those that love and desire originality and those that love customization. I have a lot of respect for any C3 enthusiast and I admire both original and custom cars. One of the things that you need to know about these cars is that most of the technology living in your C3 is almost 50 years old. Comparing a C3 to a C6 is like comparing an Apple II computer to an Apple Ipad. I purchased my first new Corvette in 1977 and I was often told that ‘it drives like a truck’. I never liked that comment and unfortunately it is not far from the truth. That is not necessarily a bad thing but, if you love driving these cars and driving them many miles then the purpose of this documentary is to help you attain a much more pleasant driving experience. One of the comments I often receive from C3 enthusiasts is ‘Your car is like a blueprint for what I want to do with mine’.
It has taken me a few years to build the car that I have now. I started with a mint, low mileage 1977 that I purchased over 11 years ago in San Diego, California. This area of North America has to be one of the most desirable climates for purchasing an older car. When I decided to start modifying this car, there were two things that my wife and I agreed upon: the car would be our retirement ‘toy’ that must remain very close to original in appearance and must be able to be driven safely, and economically anywhere we wanted to drive it. Over the past eight years I think I have accomplished those goals. I spent many hours researching components and decisions were not made lightly. I believe I have an amazing end product and I wish I could make it available for anyone to ‘test drive’.
Unless you have a huge budget, do the work over a few years. Most of the major modifications are documented in much more detail elsewhere on this website so I only plan to summarize. I have been around these cars a long time now and I am quite familiar with the common problems we often hear and read about. I am going to start with the braking system. This is probably the most discussed problem in any Corvette C3 forum on the net. While I did not have any real problems with my original system, I was still running all four original callipers, original master, hoses and lines. I wanted a braking system that would ‘stop the car on a dime and give you back a nickel in change’ and I did not think my original system was giving me that performance. My research brought me to Wilwood. Wilwood was the first company to manufacture ‘direct fit’ light weight aluminum callipers for the C3 Corvette series. I installed a complete Wilwood system including their aluminum master cylinder. I also decided this was a great time to add hydroboost. Hydroboost replaces vacuum boost with hydraulic boost utilizing the power steering pump. The combination of Wilwood braking components and hydroboost makes for an amazingly responsive braking system that will lock up all four with very little pedal effort.
Now that I could stop the car, I turned my attention to steering it. The steering system used on C3 Corvettes is of the power assist type which utilizes a control valve and cylinder mounted to the steering linkage. These systems are very prone to fluid seepage; add some slack in the sector box along with a worn rag joint and the outcome is a pretty non-responsive steering system. After researching my options I decided to go with the Steeroids rack and pinion kit. This kit replaces everything in between the steering column and the power steering pump. You have to experience this mod to appreciate it.
So now I can steer and I can stop, where to next. One of the goals I had when I started this project was to make this car more economical to drive. My original engine was an L48 and the tranny was a TH350. I was never really unhappy with this combo but I am one of those guys who think all Vettes should have been born with manual gears. These cars should have been born overdrive as well. I knew this mod was going to be lots of work but also knew it was going to be worth it. I finally decided on a TKO 500 as my aspirations never included horses over 400. I installed a TKO kit and now my car was starting to take shape.My fuel economy jumped substantially but I knew I could up it another notch by making a gear change in the differential. The 3.08 gears do not cut it with the TKO. I wanted to make more use of 5th gear so opted for 3.55 gears which was the combo I was hoping for. Fuel economy jumped again. While I was doing the gear change, I swapped out the manual clutch linkage for the hydraulic release bearing setup. That is an option that your left leg will be forever grateful.
One of the things that I noticed at this point was that the car was really shedding some weight and that the stance of the car was changing. I knew that I was going to have to address this at some point but decided to hold off until after other items had been addressed.
The odometer at this point was reading about 80k and the L48 was still running quiet and strong with no issues whatsoever. I debated for several months on what to do about the engine. Would I rebuild it or would I go the crate route, that was the question. Fuel economy was still a deciding factor and I wanted to weigh that factor with HP. I finally decided that I wanted to keep my original numbers matching engine so that my decision was now what crate. The ZZ4 kept coming back as the better choice. The HP and the engine torque values seemed to mesh well with the TKO 500. I went with the ZZ4, installed 1.6 roller rockers to resolve the premature guide wear problem with the ZZ4 heads and topped it with a Barry Grant 650 Speed Demon with mechanical secondaries. The engine is tied down with poly mounts and wears a set of Patriot ‘D’ port ceramic headers connected to the factory style side pipes. I can now drive almost 300 highway miles on a tank of fuel, so, you do the math.
After installing the ZZ4 the front of the car was sitting another inch higher. With all the aluminum components on the engine the weight loss was substantial. Now, I definitely had to address the suspension issue. I decided to address both the front and rear suspensions at the same time. There were several routes I could have taken but after spending many hours looking at the various options I went with suspension kits from Vette Brake Products. I wanted something that could be adjusted both for ride comfort and ride height. Vette Brakes had the answer with their transverse fibreglass spring kits. The heavy front coil springs and the rear steel spring are now history. I went with the dual mount rear spring kit. A nice thing about this setup is that the spring is no longer supported by the rear differential cover but by the cross member. Now both spring rates and height are fully adjustable. I installed Bilstein Sport shock absorbers on all four corners. I also replaced the rear struts with the fully adjustable kit from Vette Brakes. This kit allows you to retain the same camber settings throughout the trailing arm range. I can now say that the ride and handling of this car has been improved to the point that it no longer resembles the original whatsoever.
I know that many C3 owners are plagued by overheating problems. That was never the case with my car. Often times, C3 overheating issues can be traced to missing rad seals or air dam. My car was still running on the factory original radiator and heating core so I thought it would be a great idea to replace these. Once again the decision was to choose between a copper recore or a new radiator. After researching many radiator options the decision was simple. One of the best radiators available is the one from Dewitts. I installed the kit including the aluminum rad and dual Spal electric fans. The original alternator is a bit on the light side when running dual Spals so I installed a 100 amp GM Performance alternator. In the 5000 miles I have driven the car since the rad install I have only heard the fans power up twice.
Inside, my car sports its original mint interior with the exception of the seats. Why would anyone want to swap out the early C3 seats? The original C3 seats provide no lateral support whatsoever. A popular C3 seat swap is the Pontiac Fiero seats. There are a couple of reasons for using Fiero seats, namely: the seats have about the same dimensions and there is a company who manufactures Corvette covers for them. Brackets are easily fabricated that use the original C3 seat tracks. The Fiero seats have bolsters on both the seat and back for added support over the original seats. A downside to the Fiero seats is that the seats are about one inch higher which may pose a problem for a tall person. The solution for that is to install a set of glass T-tops and then you will have headroom to spare.
I now have a C3 that handles like a dream, sounds like a muscle car that it is not, and is a pleasure to show. With the T-tops on the deck, my beautiful wife at my side, our favourite 8-track playing, and the throbbing purr from the side pipes, the open road beckons us.