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Bringing a Corvette Big Block Back From Lethargy - Undercover Moves

Getting Down And Dirty With Big-Block Underhood Techniques

Chris Petris Nov 13, 2008
Corp_0611_01_z 1968_chevy_corvette_convertible_390hp_big_block C3_big_block 2/26

All C3 big-blocks can look this good with a little work.

All of us have been privy to or taken part in great car deals that never materialize for various reasons. This is one of the exceptions to the usual "I just missed the deal of a lifetime" story. We recently heard there was a '69 390hp big-block convertible located in central Florida for sale. The story was the '69 was in rough shape, but most of the original pieces were decent and intact. When you're dealing with chrome-bumper, big-block shark convertibles, the best policy is to move quickly. Any "deals" are always grabbed immediately. So called "deals" can put you in deep distress if you're not aware of all the problems that can arise and costs involved. So we warily headed over to look at the '69 with a few essentials, including a floor jack, flashlight, and plenty of pessimistic optimism.

The '69 was as described in rough shape, all original with an interior color change. the '69 Corvettes that are painted Daytona Yellow should have a black interior, but this car had tan leather. The windshield frame, bottom of the doors, and front-end reinforcing steel pieces were rotted from the Florida coastal environment. The owner had let the '69 sit out in the Florida sun and rain for quite a while without a cover due to an illness that he finally succumbed to. Even though he really loved the car, he just didn't have the energy to do the basics to keep the car out of the weather. But he knew what to look for when he originally bought the car; most of the parts were numbers matching and in decent shape. There were numerous parts including a windshield frame and doors that were part of the deal, plus some N.O.S. parts.

We placed a bid on the car and all the pieces, and a few days later learned we were the proud owner of the lot. The year 1969 was an incredible one for GM that included lots of high-horsepower primeval powerplants that could bury you back in the seat. That year will always be etched in my mind as the best year ever for shark Corvettes.

This particularly rough type of Corvette isn't for everyone; it will take lots of money and time to restore the car. The reality of this new project is that a total restoration will be necessary to have the car where it should be, but starting another restoration project immediately is out of the question. So why not make the Corvette drivable until the full restoration can be done? We can do that!

We knew the brakes needed repair, and the fuel system was questionable from the long hiatus off the street. The engine ran well enough (albeit the fouled spark plugs) to load the car onto the trailer, and it even appeared the engine may have been overhauled not long before the Corvette was parked. Since the rotors, calipers, hoses, and pads were original to the car, the first step was to repair the brakes. Even if the car won't run down the highway, being able to stop the car is way up on the list of important functions.

Now that the brakes have been fixed, we will focus on cleaning up the underhood area. An evaluation of all the pieces we'll need is first on the list, and then a complete clean-up will get us started in the right direction. As expected, an old-fashioned tune-up was in order, along with replacing all the vacuum hoses. After our initial inspection, we put together a list of parts to start the project and contacted ZIP Products because of their comprehensive list of detail items, especially small items that really make the difference in the final look under the hood.

It's always amazing what a difference basic cleaning makes. Just removing the dirt, grime, and grease from the engine compartment totally changes the look from just an old dirty engine to a "WOW" factor 427. As we continued on, we discovered the fuel tank had some debris but very little water in the tank. Thankfully, the problem with fuel systems that do have some basic debris is the debris takes quite a while to reach the engine. Instead of replacing the carburetor or cleaning it right away, we found it more advantageous to replace the fuel pump and blow out the lines, and then run a few tanks of fuel through the system. This usually limits the carburetor cleaning to one time, as long as you can live with the poorer engine performance while you're running the fuel through the system.

Even though the '69 is very original, we opted to replace the points and condenser with Pertronix electronic ignition components and a Flame Thrower coil. The Pertronix pieces are virtually undetectable under the stock ignition shielding, and make a tremendous difference in the starting and overall performance. Once the parts arrived from Zip Products, we began the makeover. To our surprise, we had only missed about ten percent of the parts we actually needed to do the complete job. It's almost impossible to forecast every necessary part unless the area you're working in is totally disassembled, and all the required pieces are listed during disassembly. Zip had many of the parts in stock and shipped them to us ASAP. The few parts we didn't install the first round will be installed later.

Difficulty Index

ANYONE’S PROJECT | no tools required N
BEGINNER | basic tools NN
EXPERIENCED | special tools NNN
ACCOMPLISHED | special tools and outside help NNNN
PROFESSIONALS ONLY | send this work out NNNNN


Zip Products
Mechanicsville, VA 23111
BJ's Wholesale Club



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