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by Jon Mikelonis

If there is one simplistic component that can cause more anguish for the
budget-minded performance enthusiast running a Holley carburetor, it has to be the dual feed line. The dual feed line is the mandatory component that connects each float bowl on popular "dual inlet" 4150 and 4160 model Holley carburetors while providing a place to connect your main fuel line.

Although mandatory on dual inlet Holley carburetors, the dual feed line is almost never included in the purchase of a Holley or Holley-based carburetor. The performance aftermarket is aware of this and for years popular brands like Russell, Trans-Dapt, Spectre, Aeroquip, Earl's, Holley, and Edelbrock have offered a wide range of solutions. Some simple and some complex. Some exacting and others imperfect.

A proper race setup with AN fittings and braided line is the cleanest, safest, and most preferred method for delivering fuel to a carburetor. In fact, most racing bodies frown upon more than a six-inch
length of rubber hose to carry a vital fluid, especially a flammable
one. The truth is however, not all of us race and not all racing situations require a proper race setup. On top of that, AN fittings, braided line, and the tools required to assemble them correctly (soft jaws, tubing benders, cutoff wheels, etc.) are an added expense many of us have not accepted as necessary. At least, not yet. Until then, if you
run or plan to run a dual inlet Holley carburetor you need a dual feed line of the variety that can accommodate a rubber fuel line and a hose

Although mandatory on dual inlet Holley's, the dual feed line is almost never included in the purchase of a Holley or Holley-based carburetor. The performance aftermarket is aware of this and for years brands like Trans-Dapt, Spectre, Aeroquip, Earl's, Russell, Holley, and Edelbrock have offered a wide range of solutions. Some simple and some complex. Some exacting and others imperfect. As if to provide fair warning, when a product like the dual feed line is private labeled by Summit Racing Equipment then you know it must be a hot-seller that is easy to manufacture in low-grade imported form.

The following FordMuscle product spotlight will demonstrate that just because the dual feed line performs the basic function of collecting and distributing fuel through two channels a distance no more than 16 inches, does not mean it should be produced using poor manufacturing practices. Within this review, we'll conduct a thorough inspection of five popular lines acquired from the Summit Racing Equipment Retail Store designed for Holley model 4150 carburetors, also known as "double pumpers". In the end, FordMuscle will determine the best line in terms of value and quality. As a testament to the merits of a good product, we'll keep the "winner" and return the other four to Summit Racing Equipment.

We will also prove that the most expensive option is not required if you're only looking for a practical and safe dual feed line. Thanks to an idea proposed by FordMuscle reader Tom Zuloaga, we'll demonstrate that the next time you need a dual feed line you do have the luxury of a "Make-or-Buy-Decision". Tom's clever option provides you the alternative to fabricate your very own line with steel brake tubing and brass inverted flare fittings.

A Little About Distance Between Inlet Centers
Before we report the results of our inspection there is one dual feed line nuance that requires discussion. That topic is the disparity in the value a manufacturer or distributor uses to specify the "distance between inlet centers" a dual feed line accommodates (see photo). For example, the Summit Racing Equipment website specifies that the common Trans-Dapt Chrome Fuel Line (Part No. 2197) fits Holley model 4150 carburetors with 9-1/4" between inlet centers. At the same time, the Trans-Dapt catalog and packaging specifies that Part No. 2197 is to be used on "Holley Quad" carburetors with the 9-5/16" between inlet centers. Further confusing the consumer is the value you'll find when you measure the actual distance between centers on your own model 4150. For instance, our test carburetor measures 9-7/16" between centers. A post we made on the FordMuscle tech forum asking readers to measure their own double pumper's distance between inlet centers, resulted in three out of four enthusiasts reporting values of 9-7/16".

Of course 1/16ths of an inch do not matter when you are using a flexible or adjustable model 4150 dual feed line, like the Russell Pro Street Fuel Kit (Part No. 641100) or the Holley Adjustable Chrome Fuel Line (Part No. 34-1). On the other hand, if you purchase the usual one-piece design, like the Trans-Dapt Chrome Fuel Line, then you may be in for a surprise during installation even if you do indeed have a Holley model 4150.

In search of the truth and the possibility that not all model 4150's have the same distance between inlet centers, we went straight to the source and called the Holley tech line. The tech we spoke with informed us that their print catalog erroneously reports that the center-to-center distance of the one-piece Holley Fuel Line (Part No. 34-150) is 9-1/4". For the accurate measurement he suggested we refer to the website where the value is listed as 9-5/16". We found all this information odd given the fact that a similar Holley one-piece line designed for 4150's, fit our BIGS 950 spot-on. As we mentioned earlier, the BIGS had a center-to-center distance of 9-7/16". We didn't challenge the Holley tech and simply concluded that when buying any manufacturer's one-piece dual feed line, don't be surprised if you need an RGA number.

Let's begin our product review with the Russell Pro Street Fuel Kit.

Russell Pro Street Fuel Kit
Part No. 641100
Summit Racing Equipment Retail Price: $69.95

The Russell Performance Products brand has carried a reputation for manufacturing quality fluid transfer components for more than 25 years. In 2001 the Russell name became an Edelbrock brand. This explains why you will often see Russell components in Edelbrock packaging. We got our inspection started with the Russell Pro Street Fuel Kit. No wonder, it's a great looking piece and the most expensive one in our comparison.

The Russell Pro Street Fuel Kit uses anodized aluminum fittings and -6 or 3/8" stainless steel braided hose. The fuel inlet is 3/8" NPT, allowing the use of a NTP-to-hose barb or a NTP-to-AN fitting. This particular kit comes with a 0-15 psi fuel pressure gauge suitable for the 1/8" NPT gauge port. The built-in flexibility of the Russell piece eliminates any chance of non-compatibility due to variation in distance between inlet centers.

Let's take a closer look at the Russell Pro Street Fuel Kit:

What's inside the package? It's good to see that for $70 you get some well-illustrated instructions and a fuel pressure gauge.
The Russell kit requires that you change the steel Holley fuel inlet fittings with these aluminum "male" fittings. By enlarging the picture you'll see why we were a bit surprised with the partially marred initial threads on this fitting.

A peek into the main inlet was disappointing. The Russell website says their parts are manufactured in a QS-9000 certified facility.
We may be knit-picking, but something tells us that the QS-9000 quality management system was designed to prevent defects like the one found in the main fuel inlet. Manufacturing shavings and burrs are not abnormal but there was nothing precautionary mentioned in the instructions about this possibility.

To establish a baseline to compare the Russell Pro Street Fuel Kit, as well as the other four dual feed lines, we measured the inner diameter of our Holley carburetor's fuel inlet fittings. They measured .275 inches.
Since the Russell line used its own fuel inlet fittings we measured their inner diameter too. They both came in just below .300 inches.

The primary and secondary legs measured .260 inches.
Installation was quite simple. First we removed the standard Holley fuel fittings from each bowl. We reused the Delrin washer included on the BIGS carb. Russell supplies much thinner metal washers that also work well.

Again, the flexible line allows for a disappointment-free fit.

Keep it or Return it?
Return it. The decision to repackage the Russell Pro Street Fuel Kit and return it to Summit Racing Equipment was not too difficult based on the burrs and marred threads we discovered. Although the unit is well designed, the production flaws were intensified by a relatively high price tag. Objectively, when you spend $70 you shouldn't be expected to pick out shavings with a pair of hemostats. This was unfortunate, because the Russell Pro Street Fuel Kit is a fine looking unit that matched the carb quite well.


Trans-Dapt Chrome Fuel Line
Part No. 2197
Summit Racing Equipment Retail Price: $14.95

Many of us grew up learning to avoid Trans-Dapt parts due to poor fitment and their reputation for peddling cheaply cast imported parts. FordMuscle cannot say the factoid is applicable to all of Trans-Dapt's products but they sure lived up to the reputation during this evaluation.

At this point, we would have preferred to show a picture of the Trans-Dapt Chrome Fuel Line affixed to our Holley 4150. However, contradictory to Trans-Dapt's declaration of "No Bending Required", their dual feed line would have indeed required bending to fit our carburetor. See the second caption below. In fairness and just as we discussed earlier, the Trans-Dapt catalog specifies their line fits Holley "Quad" carburetors with 9-5/16" between inlet centers. Although our test carburetor is a Holley "Quad", it does not have 9-5/16" between inlet centers. Regardless of the obvious fitment issues, you'd have to be a fool to put this $15.00 scrap on an $800 modified Holley. The captions below prove the old adage "You Get What You Pay For".

Trans-Dapt 2197 is a one-piece chromed steel design with a 1/8" NPT provision for a fuel pressure gauge. Nothing more than the line itself is included in the package. However, at $14.95 we didn't expect much.
The most notable characteristic of Trans-Dapt 2197 was the inability for us to install it on our Holley 4150 without making a serious tweak to the line. We chose not to force the issue.

Whether you are running a Holley 4150 or not, as a consumer you better be sure your carb has 9-5/16" between centers or this piece will not fit without bending. Can anybody who owns a Holley 4150 with 9-5/16" between inlet centers please step forward?
Trans-Dapt still hasn't learned that chroming the threads and flares on their fuel lines is a great way to promote a bad seal. This close-up also shows the rough bend made in the secondary leg. Gee whiz.

This picture shows the Trans-Dapt line up against the Summit brand equivalent. While both brands make the mistake of chroming the fittings and the flares, note the reduced inner diameter of the Trans-Dapt line (top right).
The tube diameter at the flare measured .225 inches, offering the greatest mismatch of all the lines tested. That was enough, we taped the line back onto the Trans-Dapt shrinkcard and prepared it for Summit Racing Equipment returned goods.


Keep it or Return it?
Return it. Based purely on principle we highly recommend not using the this Trans-Dapt dual feed line. Here's a quote from the Summit website about TRD 2197, mostly likely written by or approved by Trans-Dapt copy writers:

"With large 3/8 in. diameter tubes, these TD Performance fuel lines provide excellent fuel delivery along with a shiny chrome finish to dress up your engine compartment. They're perfect for directing fuel to your Holley carb."

Compare the above quotation with the last caption of the TRD 2197 evaluation and draw your own conclusion about this part. By the way, 3/8" can also be expressed as .375". If the Trans-Dapt 2197 was the last dual feed line on the planet and you didn't have the capacity to build your own, we would suggest converting to fuel injection.

(Holley and Edelbrock)
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In This Article:
FordMuscle takes an insightful look at the performance aftermarket's array of popular dual feed lines. We'll point out manufacturing shortcomings and show you where your money is best spent. Additionally, we'll demonstrate how you can make your own line in FordMuscle step-by-step fashion.


To initiate our dual feed line comparison, we made a quick trip down to the Summit Racing Equipment Retail Store to pick up the parts. We headed back to the garage with five very popular "hose & clamp" style dual feed lines and a bad attitude about all the bow ties in the Summit parking lot.

We analyzed each dual feed line for manufacturing quality, fitment, and inner diameter. With a better understanding of each manufacturer's product, we revisited the cost of each to determine the best value for your dollar.

Finally, we took a stab at making our own with steel brake line tubing and brass inverted flare fittings.











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