photos by: Alex Healey and Rick Seitz
Holley Performance Rebuilds our OEM/Holley DZ-302 Carburetor
One of the best kept secrets (or worst, depending on who you ask) about Timeless Muscle Magazine, is the rather vast array of classic iron project cars we have in dire need of attention to restore them to their former glory. In addition to our ’68 Firebird and ’70 Chevelle SS, we also have a ’69 Chevy Camaro Z/28 you’ll be reading more about very soon. We show a lot of very modified and incredibly upgraded classic American muscle cars here, but we also respect the art of restoration. This ’69 Z/28 will be brought back to it’s showroom freshness, and we’re glad to be sharing various parts of the process with you.
One of the things that caught our attention was the original DZ-302 Holley 4-barrel carb. It was looking a little dingy and although it was reportedly rebuilt back in the ’90s, we felt that the time was right to bring it back to new condition. It has all the correct stampings, the numbers are all correct, and it needs to work like new, so we want to keep it and make it look and function as good as it did when new.
There are many paths that we could have taken with this, including an off-the-shelf rebuild kit from our friends at the famed carb manufacturer, but we ultimately elected to take it a step further and have it rebuilt through Holley’s internal “Custom Speed Shop.” Located in-house at their main headquarters in Bowling Green, Kentucky, the carb masters know their own products better than anyone. They have all the parts, pieces, tooling, and experience required to completely remanufacture any vintage Holley and make it new once more.
Holley offers this service for OEM vintage carburetors of the Holley variety; such as the DZ carb we have, or for various other GM, Ford, Chrysler and AMC vehicles. We figured, if we’re going to have it rebuilt, anyway, might as well have it rebuilt by the folks who designed it, right?
Now you may be thinking, “…there’s no way I’m shipping off my original, numbers-matching, priceless carb off to a shop in Kentucky- there’s too much risk of it being lost or stolen.” Trust us when we say that we understand your concern, but those guys at Holley treat every component that comes into the in-house Custom Shop as one of their own.
This specialty service transforms tired, worn-out O.E.M. muscle carbs back to their original condition in appearance and function. And because this is a “custom” service, each order is personally followed through from start to finish by one of the factory technicians. Follow along as our original DZ fuel mixer gets the full treatment!
Of course Holley carbs are given new life at the Holley Custom Shop, but we were pleasantly surprised to learn that Rochester, Motorcraft, and Carter carbs are all restored here too. Engineering parts lists are uncompromisingly followed to the letter. In some remote cases where an O.E. part may no longer exist, an O.E. “equivalent” is used in its place. Before any work begins, the responsible technicians at the Holley Custom Shop take two or three close-up photos of each carb from different angles so that it can be easily identified at any time during its stay at the Custom Shop. Many more precautions as well are taken to ensure your order stays together. Here are some other important reasons why the Custom Shop’s restoration process stands out in customer satisfaction:
- Carbs are inspected for metal fatigue, slightly-stripped threads, hair-line cracks and worn-out throttle lever bushings.
- Cadmium Chromating of steel parts (clips, fasteners, linkages, etc.) for correct O.E. appearance and corrosion protection.
- Black oxidizing of base plates (on Rochester 2-BBL carbs).
- Chemical and vibratory cleaning of all carburetor castings.
- Testing of sub-assemblies, including chokes, vacuum secondaries, float bowls, and metering blocks, to verify performance before final assembly takes place.
- Replacement of all gaskets, diaphragms, seals, power valves and needle/seat assemblies.
- Flow bench testing of all carburetors to confirm correct metering of air/fuel volumes.
NOTE: Prices are based on rebuildable cores (no damaged castings, stripped threads or missing parts.) All damaged or missing parts will be repaired or replaced and a charge will be added based on replacement value. You can contact the Holley Custom Shop directly for specific pricing information.
Dichromate plating restores stripped-down carburetor parts to their factory-original appearance. This is the correct factory gold/brown finish which has appeared on many standard and performance Holley models over the years.
Upon arrival at the Custom Shop, carburetor castings are immediately entered into a unique tracking system that all but eliminates the chance of a part becoming lost or being returned to the wrong customer. In fact, parts are also photographed to avoid any look-alike problems.
After going through a series of extensive cleanings, each casting sports a smooth, even dichromate coating that is indistinguishable from a new carb in every respect, including color.
Besides Holley models, the Custom Shop services Rochester, Carter and other brands of carburetor as well, both two- and four-barrel units. All work performed by the Holley Custom Shop is covered under a limited warranty and is guaranteed to live up to its expectations.
Like color powder coating, plating does not interfere with the original design of a part. In fact, it helps by providing extra protection against damage, thus extending the lifetime of the part. Whichever plating you choose, it’s sure to be a hit.
When sending in parts for service, you are required to obtain a Custom Shop tracking number from Holley Technical Service by calling (270)781-9741 before shipping in your package. This tracking number must be clearly marked on the shipping label and on a minimum of two sides of the box. Please carefully pack all pieces to help prevent any in-transit damage. Also, use a reliable shipping company that offers insurance protection against loss.
For pricing or service options, you may also call between 8:00 AM – 5:00 PM (CST), Monday thru Friday at (270)781-9741. Or, visit the Holley race trailer at most NHRA tracks and other national competition or motorsports events.