From its earliest beginnings in 1902 as an automobile manufacturer, Holley has been all about creating carburetors that offer a greater level of performance. Half a century later in 1952, when the first four-barrel carburetors were introduced to the market on Cadillac V-8s. They were the Carter WCFB and Rochester 4GC and found their way onto Chevrolet passenger car V-8s as a performance option when the 265-inch small-block engine was introduced in 1955. The four-barrel Power Pack option included better flowing "pyramid" heads with a 9.5:1 compression ratio compared to the standard 8.5:1 compression ratio equipped with a Rochester two-barrel carburetor. On the other side of the fence, Ford offered a Holley four-barrel carburetor as a performance option for the Y-block V-8. In 1956, Ford was the first manufacturer to introduce light-duty trucks available with a high-performance engine option. Surpassing the '56 Chevy trucks, offered only with a detuned version of the passenger car 265-inch V-8, Ford made the larger 272-inch Y-block engine available in three stages of tune. The standard option V-8 is known as the light-duty 2V 272 (two-venturi, two-barrel carb), and the truck's original engine can be identified by locating a V in the VIN number on the aluminum serial number tag held on with four Phillips screws located above the lower hinge pocket on the driver side. If the tag is missing, as they often are, look for the VIN number stamped into the topside of the passenger-side framerail right in front of the firewall. If all else fails look at the VIN number printed on the pink slip (title).
Swapping out an old Holley...
Swapping out an old Holley carburetor for a new one is easy with a Holley direct replacement carburetor, such as Holley's new quad intended specifically for small-displacement V-8s and larger V-8 dual-quad applications.
Next up is the Z code heavy-duty 2V 272 identified with a Z in the VIN number. One might suspect heavy-duty means the engine has a heavier bottom-end, but as we've been informed it refers to larger-valve cylinder heads with better porting. Top of the line is the R-code 4V 272 equipped with a Holley four-barrel carb and the good heads. Of course the odds of a '56 Ford pickup still having its original engine are slim, but in the case of our one-owner Barn Find '56 we know the pale Ford Yellow short-block is the engine that came in the truck. Since there's a V in the VIN number, and the heads and four-barrel intake are factory painted in an original 292-inch Y-block Red we know the R code upgrade was added at a later date by the original owner. We've yet to discover a real R-code '56, so they must be rare, but it's interesting to note there never was a letter or digit in the '56 VIN to prove a truck with a Big-Window cab came from the factory that way.
What all of this has been leading up to is we decided to swap-out the vintage "square-bowl" Holley four-barrel carb we inherited and slap on an Original Holley Performance 390-cfm Four Barrel Street Carburetor. The new Holley is the best way to gain extra horsepower, get better fuel-economy, and lower emissions for any application that requires a smaller four-barrel to ensure it won't be over-carbureted. Read on and we'll explain what the benefits of the square-flange model 4160 Holley are for the Y-block Ford engine and how we went about installing it on our 272.
Since the Holley square-bowl's...
Since the Holley square-bowl's power valve was leaking gas externally and most likely flooding internally as well, we figured it was a good excuse to step up to a more modern carburetor.
The first step was to disconnect...
The first step was to disconnect the throttle (gas pedal) linkage which was easily reattached to the new Holley 4160 because it is engineered to be a direct-replacement for the Ford Y-block engine.
Next, the four 5/16 fine-threaded...
Next, the four 5/16 fine-threaded base nuts on the square-flange Holley were easily removed with a Craftsman open-end/box ratchet-wrench.
After the neoprene fuel line...
After the neoprene fuel line (black hose) was removed by unscrewing two stainless steel hose clamps we were able to slip the box-end over the steel line and turn the fitting without rounding-off the flats.
The next line to disconnect...
The next line to disconnect was for the vacuum supply to the stock Ford distributor with vacuum advance. The Holley 4160 has a timed spark vacuum source that was reconnected to the distributor.
Notice the new Holley 4160...
Notice the new Holley 4160 at left has smaller venturis than the old square-bowl Holley at right. The smaller size venturis create higher velocity at lower speeds and produce better low-end throttle response.
A quick, light tap to the...
A quick, light tap to the old Holley separated it from the base gasket and then it was lifted straight up to remove. We were very careful not to scrape the old gasket into the intake manifold.
To guarantee none of the old...
To guarantee none of the old gasket material fell into the engine via the intake manifold we used a wet-and-dry industrial vacuum cleaner to suck away all of the old chunks.
Notice how using a single-edge...
Notice how using a single-edge razor blade to scrape the cast-iron manifold's deck left a perfectly flat surface to mount the part number 0-8007 Holley 4160 square-flange carburetor on.