Through the first six installments of our project series, we've covered project planning, chassis and suspension, engine, drivetrain, brakes, installing C5 seats in a midyear, engine electronics, exhaust, fuel systems, and the exterior features of the body. In this installment, we'll feature the engine-compartment modifications, and cold-air intake and cooling systems.
We've tried to cover each subject in enough detail to give you a good idea of what's involved, the sources we used, and the reasons for our approach. At the very least, we hope it will stimulate some ideas and save you time, but the fun of these projects is coming up with your own ideas to build a car reflecting your personal taste and achieving your own objectives. Since each project is unique, and you'll have your own ideas on the approach to take and components to use, we'll just describe the approach we've taken and what has worked for us.
To complement the work on the engine, we went to some lengths to enhance the appearance of the engine compartment. The major changes to the body involved reworking the firewall, inner fender panels, and hood (which were done at the Corvette Center in Newington, Connecticut), and the design of the cooling and air-intake systems.
Engine Compartment Firewall
The firewall was smoothed and all unnecessary holes filled. One particular aspect we wanted to change was the wiper-motor area. A new filler piece was made on the driver side of the wiper-motor opening, which mirrored the shape on the passenger side to make a uniform opening. An access door was then made to fit the new wiper-motor opening, which fits flush with the firewall and is held in place by two tabs. To gain enough clearance, the windshield-washer assembly was removed (a new cover plate was made to enclose the motor), and we also had to modify the four wiper-motor mounts to recess the motor another 1/4 inch to make the cover fit flush with the firewall.
We also wanted to hide the hood latch cable as much as possible, and we ran the cable (using a lawnmower throttle cable) along the inside of the firewall. (See photos 1, wiper recess; 2, finished wiper door opening and firewall in primer; and 3, painted firewall.) In photo 3 you can see the two-tone paint scheme of our red and Quicksilver and how the transmission tunnel was modified. Since the frame is red, we wanted to have more contrast against the underside of the body, and the silver really helps to distinguish the frame.
Additional changes to the firewall included fitting a parking-brake setup from the '64 Corvette (the '64 style fits much closer to the firewall), mounting the hydraulic-clutch master cylinder and reservoir, installing a bulkhead (from Vintage Air) for the A/C and heater lines, and mounting the Engine Control Unit.
In addition to smoothing the inner fenders and making clearance for the C5 upper control arms, three other major changes were made. The first was to install a battery-access door (from an A/C car) in the driver-side fenderwell. Moving the battery to that side was necessary because we relocated the dry sump tank on the passenger side. As a side benefit, this also helped gain easier access when installing components such as the ECU, the brake system, and the hydraulic clutch. (See photo 4, battery access door.) The second was to extend the inner fender panels by making new covers to enclose the upper control arms in lieu of using rubber dust shields. (See photo 5, control-arm cover.) The third was to make a hidden tunnel for the wiring that normally runs along the inside of the driver's fenderwell. The "conduit" runs along the underside of the fender peak and works well to enclose all the wiring. We used a length of fiberglass panel and glassed it in place. From the underside, you can't tell it's there, so we don't have a good picture of that.
Changes to the underside of the hood included filling, smoothing, and radiusing each seam and joint; making a recess to clear the dry sump tank; installing detachable hood hinges from American Freedom Products; and using a gas strut for the hood support, which was sent to us by a friend from Australia. The hood strut is from a BMW which was just the right length. We used the stock upper and lower brackets from an original hood support and mounted them in the stock locations on the hood and fenderwell. We were surprised at how well it worked. The hood latches were smoothed and chromed. The main advantage of the quick-disconnect hinges is in allowing you to remove the hood without removing the hinge bolts so you don't have to realign the hood again. (See photo 6, hood hinges; photo 7, hood underside; and photo 8, hydraulic hood support.)
The folks from the Pro-Fab shop of Be Cool (Marks 7 Machine) constructed the radiator, radiator mount, A/C condenser, and expansion tanks from our designs. Their work was outstanding, and everything fit perfectly. The radiator has both the upper and lower inlet/outlet on the passenger side to gain more space in the center of the engine to allow room for the cold-air intake system. Braided stainless hoses and AN fittings were used throughout. The upper and lower radiator hoses were found by searching through the hoses in our local NAPA parts store. It may seem unusual, but the upper hose is from a Ford pickup (PN 8779), and the lower hose from a Pontiac V-6 (PN 9050). To match the other braided hoses, we used 1 1/4-inch braided Spectre hose covering which was tough to install but worked well. The thermostat housing is a 35-degree angled swivel unit from Street & Performance, and the hose ends are also from Street & Performance. (See photo 9, radiator/upper mount; photo 10, expansion tank; and photo 11, upper radiator hose.)
Twin Spal fans mounted to a shroud were used along with a Spal electronic control system, which allows you to set the temperatures for the fans to turn on and off. This shroud has rubber flaps which open at driving speeds to allow more air through the radiator. (See photo 12, fans/shroud.)
This was a tough one. We laid out several approaches which would gain access to cooler outside air and find the best route. The main considerations were how well the intake could be integrated into the body as well as the best route to take to get to the engine. Other factors were the type of ductwork that could be made, and how we could make the connection to the throttle body and incorporate the mass airflow and incoming air-temperature sensors. Space is at a premium when you're looking for a route that passes through the chassis, under the radiator and steering rack, and squeezes between the steering rack and the engine damper. The approach we used begins with a scoop which was molded into the front valance. The scoop incorporates a custom grille and air filter and, further upstream, a combination of silicone and metal ductwork to connect to a custom throttle-body elbow made by Street & Performance. (See photo 13, cold-air scoop and grille; and photo 14, ductwork and throttle-body elbow.)
The intake grille and scoop is located between the bumpers and molded into the front valance. The grille is a custom piece machined by a local machinist to our design. The design uses horizontal grille bars to follow those of the original grille. Behind the grille is a custom air filter we made ourselves using K&N red foam filter material. The scoop was made, starting with a small aftermarket hoodscoop and then extensively modified to blend into the valance. The rear of the scoop was shaped to fit an aftermarket C4 silicone "bridge" which fits into a 90-degree silicone elbow and then makes the upward turn under the steering rack. From that point, an ovalized tube was used to make the connection to the throttle-body elbow.
Space between the steering rack and engine damper was extremely tight. After searching for ways to maintain a 4-inch-diameter tube, which would be narrow enough to fit that area, we found a company called Dr. Gas, which makes oval-shaped tubes from round stock. The company can ovalize a 4-inch round tube down to 2 3/4 inches, however, we had to go further to get the size we needed. One issue you run into when ovalizing a round tube is that it can end up forming a figure-eight shape if you're not using a mandrel. To avoid that, we made a series of wooden jigs to fit inside the tube while we squeezed it further in the vise. We were able to maintain the round 4-inch shape at the top of the tube for the connection at the throttle-body elbow, while achieving an oval shape at the bottom to clear the engine damper.
Engine And Engine-Compartment Finishing TouchesIn Part 3 of our project series, we mentioned some of the finishing touches applied to the engine, such as the smoothed and painted block; the polished heads; the water pump; the dry sump tank and throttle body; the accessory mounting brackets; the serpentine belt system; and the chromed valve covers, oil pan, starter, A/C compressor, alternator, power-steering pump, and coil mounts. However, we've not yet shown what the finished engine and compartment look like with the additional components we've added since then. These include the engine covers, intake manifold cover, power-steering reservoir, battery box, steering linkage, and the brake-master cylinder.
Since we wanted to maintain as much recognition as possible with the LS7 Z06 engine, we had to retain the stock-style engine covers. However, there were several changes made to them, including smoothing and painting them in our red body color. The recessed lettering on the covers was highlighted by using silver pinstriping in an outline fashion. This was done by hand by a local friend of ours at Scavotto Signs. The covers were also modified to gain clearance for the A/C compressor, the brake master, and the intake manifold cover. (See photo 15, engine cover.)
Several years ago we designed a cover for the intake manifold of our '62 Corvette, which had the LS6 engine. This time we wanted to do something similar, however, we wanted it to be a modern interpretation of the original '63 fuel-injection cover, so this one has more of a finned design. We worked with Austin Barnett of VetteORama to design a custom emblem that uses crossed flags with "Z06" and "427" on either side. The cover consists of a framework held in place with brackets, mounted to existing intake-manifold bolt locations, and the billet-aluminum cover itself. Austin also made the "Split Personality" emblem mounted on the wiper door. (See photo 16, intake-manifold cover.)
A remote reservoir from Street & Performance was used. It was a tight fit but just cleared the inner fenderwell and radiator. Braided stainless hoses and AN fittings were used for the connections to the P/S pump and steering rack. (See photo 17, P/S reservoir and lines.)
In Part 3 of our project series, we showed the new battery mount made on the driver side of the chassis. We also had a billet-aluminum battery holder made and added a little more detail by gluing the emblem from the '63 glovebox to the top. Braided stainless-covered battery cables were also used, along with a battery-disconnect switch, and the terminals were smoothed and polished. We used an Optima "Red Top" battery but went the additional step of painting it in the red body color. Access to the battery is gained through the door in the driver-side fenderwell. (See photo 18, battery box, battery, and cables.)
We used a midyear-style tilt column from Flaming River, which we'll cover more of in the next installment. From the end of the steering column, we made the steering linkage using stainless components from Borgeson, which we then polished. The linkage includes four pieces: one combination universal/damper, one length of 3/4-inch steering shaft, one universal, and one support bearing. We found that an easy way to determine the proper lengths and angles is to mock up the linkage using a dowel for the shaft. The linkage connects to a chromed C4 Corvette rack-and-pinion unit from Unisteer. (See photo 19, steering linkage components; and photo 20, steering linkage installed.)
We also used a billet mount from Flaming River at the firewall to hold the column in place. One note on the firewall mount is that the diameter of the hole through the mount is larger than the diameter of the steering column. A friend of ours from Canada made a bushing to make both fit together.
Brake Master Cylinder
In Part 3 (Apr. '07) we showed a picture (page 48, picture 18) of what the electric/hydraulic power unit looked liked when installed on the chassis. Photo 21 of this installment is a picture of what the brake master looks like when installed. Because the power unit is mounted below on the chassis, only the brake master is mounted to the firewall which gains more space on the firewall. This unit (model No. 10-56) is from ABS Power Brakes.
Next time we'll cover the interior features of the car, including the overall design, upholstery, gauges, A/C system, insulation, rearview mirror/monitor, and custom panels. In the meantime, there are additional pictures and information on our website at www.richsclassic corvettes.com. We're always glad to try to answer any specific questions you might have about our projects.