There's no denying that vintage engines have come of age. Look around and you will see plenty of Hemis, Nailheads, Y-blocks, and, yes, arguably the king of vintage motors, the Chevy W-motor (348/409). (And for those fans of Street Rodder you have already noticed the vintage engine series over the past few issues. This issue has the Rocket 88 bent eight.)
While you may feel good about rounding up one of these yesteryear powerplants, the real trick isn't as much getting parts and pieces to screw the motor back together, but rather how to "top it off." Carburetion, my friend, the controlled fuel leak; yesteryear's technology, but to all hot orders there is nothing like vintage carburetion (that works!) to really set off your vintage engine.
Finding these vintage carbs is a challenge, but they are out there. The real trick is to get them back into topflight working order. Something you would actually trust driving. That's where the Holley Custom Shop comes neatly into the picture. For decades I've had a pair of Chevy Rochester 4-Jet carbs that were originally intended to go on my early Corvette. Well, the story about best-laid plans and the Corvette is long gone, but the carbs were neatly tucked away in my garage. I find myself talking to Matt Held of Holley about these carbs. He then reminds me of the Holley Custom Shop that repairs vintage carbs of all types, not just Holley's. Then the proverbial light bulb went off. On an earlier trip to Holley I had gone through the shop and was fascinated by just what they did have to bring back to life those old "leakers." (Holley is located in Bowling Green, Kentucky, some 115 miles south of Louisville.)
I can hear it now: "But my carburetors aren't Holleys." Not to worry. The Custom Shop will return any Holley, Carter, Motorcraft, or Rochester carburetor to original-equipment appearance and performance. There, does it get any better? Follow along and we will take you through the refurbish treatment of our tired 4-Jet carbs.
Inside a bustling maze of...
Inside a bustling maze of state-of-the-art assembly lines, Holley's Custom Shop is an oasis of old-school craftsmanship. In contrast to the hundreds of employees who assemble Holley's current-production carbs, just one person handles each custom shop carburetor. The skilled hands of Gary House rebuilt our Rochesters.
When each carburetor arrives,...
When each carburetor arrives, it's tagged, photographed, and a work order is started. (Here's a tip: since the carburetors are completely disassembled and re-plated, House recommends that multi-carb setups are sent together to ensure that they match when finished.)
While House has seen worse,...
While House has seen worse, our carbs were nowhere near show-quality. He begins disassembly with the linkage and the main body screws.
Most old carburetors have...
Most old carburetors have suffered from many ham-fisted mechanics. The Custom Shop is equipped to fix just about any curveball thrown their way. The most common malady is stripped threads, which are fixed with a Helicoil-even stripped fuel bowl inlets on Holleys!
House makes quick work of...
House makes quick work of tearing down our carburetors.
One of our carbs was retrofitted...
One of our carbs was retrofitted with an electric choke kit; the proper hot-air choke will be sourced and installed upon assembly.
The original throttle plate...
The original throttle plate screws are staked into place. House uses a tiny belt sander to grind them down before removing them.
Parts are separated into groups:...
Parts are separated into groups: steel for cadmium chrome plating, zinc for dichromate, steel for black oxide, and non-ferrous for vibratory polishing and/or cleaning. Damaged parts are replaced, but not discarded (saved for reference). Small parts are wired together to prevent loss during the plating process. House dislikes fishing tiny parts from the tanks.
Missing, damaged, or incorrect...
Missing, damaged, or incorrect parts are salvaged from Holley's "carburetion graveyard." Our missing hot-air choke was rescued from these bins.
There are also many parts...
There are also many parts that vary from carburetor to carburetor depending upon its intended application (such as secondary spring rates and jetting). These "variable specifications" are recorded in numerous manuals...that are worth their weight in gold! Countless hand-written notes accompany the printed specs to reflect updated part numbers or knowledge gained through generations. House adds, "These books were given to me, and I'll pass them onto the next person."
All but the most delicate...
All but the most delicate parts are carefully media-blasted prior to plating or vibratory polishing.
The steel parts are processed...
The steel parts are processed with this automated yellow zinc cadmium chrome plating process.
A few dunks in these cleaning...
A few dunks in these cleaning tanks were all it took to get these brass floats bright and shiny.
Our carb's major bits are...
Our carb's major bits are clean, plated, and ready for re-assembly. Note the cast base plate that's been given the black oxide treatment-just like when it was new.
Small spaces (such as these...
Small spaces (such as these emulsion tubes) are checked to make sure they didn't suck up anything during the cleaning or plating processes.
Once it's reassembled, the...
Once it's reassembled, the carburetor is affixed to a flow stand. Vacuum ports are plugged and hoses attached. The stand uses mineral spirits instead of gasoline. They behave similarly on the stand, but mineral spirits are considerably less dangerous.
With fuel pressure applied,...
With fuel pressure applied, the carburetor is checked for leaks and the float levels are set. Accelerator pump operation is checked with a twist of the throttle arm.
House opens the vacuum valve,...
House opens the vacuum valve, and the carburetor's air/fuel ratio is checked from idle to full-throttle. Even operation of the spark advance is verified. This aspect is what separates an average carburetor rebuild from a Holley Custom Shop Rebuild and Return. House confirms, "I can't imagine rebuilding a carburetor without testing it on a flow stand! How can you be sure it's going to work to O.E. specifications?"
House records any parts he...
House records any parts he replaced and adjustments he made to the carburetor on the work order. All paperwork accompanies the carburetors when returned to the customer.
Here you can see a comparison...
Here you can see a comparison between an un-restored carburetor, and one given the complete Custom Shop treatment. The cleanliness and attention to detail is outstanding.
The Holley Custom Shop folks...
The Holley Custom Shop folks take pride in their work, and it shows. Here House holds one of our completed carbs before carefully packing it for shipping.