Bringing a Corvette Big Block Back From Lethargy - Undercover Moves

Small things like this carburetor return spring make the difference. The original spring was thrown away years ago, and a door closer spring was installed. Stiffer springs wear out the carburetor's throttle shaft quickly. We were able to brass brush the throttle cable mounting bracket, leaving the original coating. Once any bracket is chemically or mechanically stripped, a coating must be reapplied to prevent corrosion.

Since our original carburetor's air cleaner mounting stud was missing, Zip saved us with the unique original-type air cleaner stud. As you can see, the intake manifold looks much better, and things are starting to take shape. We cleaned the exterior of the carburetor with the carburetor cleaner before installing it on the intake.

Replacing the fuel pump isn't the easiest thing to do, but with the right tools, it isn't so bad. We found that a long extension with the universal socket that can be used from the fenderwell works best. You can see the extension is coming in from below the upper control arm. The fuel supply and return hoses were replaced along with the fuel pump. We replaced the pump because of the debris in the tank. This debris fouls the fuel pump check valves, and the pump output is diminished. Zip supplied us with an aftermarket pump because we didn't want to fill a new correct pump with junk. After we run the engine for awhile, and everything checks out OK, we can change to a numbers-matching fuel pump.

We installed the Zip Products-supplied spark plug wires, paying close attention to where the shielding ends on the plug wires. The instruction sheet proved to be correct, and they also mention the correct distributor cap placement. If the distributor is installed incorrectly, the plug wires won't fit properly.

We always apply a dab of silicone dielectric grease to ease plug wire boot installation and removal. Too much grease and the boots want to slip off. A dab the size of a wooden match works best. On at least half of the plug wires, we had to grab the terminal in the spark plug end and pull it out to meet up with the edge of the boot where the size increases to accommodate the spark plug porcelain. You should feel a click when the plug wires are installed properly.

We installed the Pertronix Flame Thrower ignition coil to pump up the spark voltage. The Pertronix coil fits in the stock bracket and is shorter than the original coil, making plug wire installation easier. All wiring info is provided, and the coil connection terminals are provided in the Pertronix Ignitor kit. The original resistor ignition power wire coming from the harness should be replaced with an ignition power wire coming off the pink wire at the ignition switch.

One of the original pieces we cleaned up and reinstalled was the ignition lower shield. The Pertronix pieces are a good choice since you don't have to remove the cover and shielding to access the points all the time. Once the shield is in place, the plug wires can be installed. If the distributor is in the correct position, the plug wires and shielding grounds will fit properly.

These are the small things that make engines run well. PCV valves have calculated vacuum flow rates for the engine they were designed for. When incorrect PCV valves are used, performance suffers. If the flow rate is too low, engine contamination from condensation can occur. We also replaced the PCV valve grommet to keep vacuum and oil in the engine.

We wanted to change the variety of cooling system hose clamps that the engine had with OE-style clamps from Zip. Everybody hated these clamps that worked with them regularly because they were difficult to release until you figured them out. Place a screwdriver between the hose clamp band and the hose, then give the screwdriver a twist to release them.

Ever since we first started the car, we had no oil pressure showing on the oil pressure gauge. We found the block fitting was plugged, and the oil line was cut. Zip Products supplied the correct steel line and fittings. We also used their line bracket to replace the missing bracket. We weren't overly concerned since the engine was quiet, but it's nice to know the correct oil pressure is there now that we'll be driving the Corvette occasionally.

We moved inside the car to remove the center gauge cluster and replace the plastic oil line. The first piece to remove is the map pocket dash panel and then the wiper switch plate. The radio knobs and the nuts that hold the radio to the plate must be removed to pull the plate out of the console and dash. Originally, the center gauge cluster had two 31/48-inch hex nuts holding it to the center console that must be removed. Most of the time, the nuts are left off during reassembly. If the plate is tight to the console, the nuts must be removed.

Now we can install the new plastic oil line on the oil pressure gauge. Watch the routing of the plastic oil line. It can be pinched during dash reassembly. While we were inside the car, we also replaced the accelerator cable. The accelerator cable on the '69 has a 71/416-inch hex-head screw directly above the accelerator pedal assembly, holding the cable on the firewall from the inside. Job done.