3-Hole Big and Ugly Hat Style Injector EFI Kit for 6-71 Thru 14-71 Blowers


The Big and Ugly was possibly named for its’ unavoidable in your face presence, and if you are looking for the boldest of statements, then rest assured this is the ultimate pick! The BAU is available with numerous butterfly sizes and progressive linkage. We highly recommend the progressive linkage for smoother throttle transition and we’ll match the butterfly size for smooth street driving or to feed monster horsepower and big cubic inches. So let the professionals at Hilborn supply your Enderle injector, convert your original or supply a complete EFI Kit.

Contact us to place an order or get a quote.

California customers please see “Emissions Notice” tab below.

  • Hilborn EFI kit with Holley HP ECU starting at $8070

Product Description


The Enderle Big and Ugly offers enough versatility to fit a diverse range of applications, from a low horsepower small block Chevy to 600+ cubic inches on methanol. With that said, the BAU has become our go-to injector for the larger cubic inch applications especially on gas. In an EFI application, we can correctly lean out the fuel producing a tremendous amount of vacuum signal on the back side of the butterfly that can negatively affect throttle tip-in drivability. The BAU offers two distinct ways to reduce or eliminate the following tip-in issues.

First, using the optional progressive linkage, we can completely shut the two secondary butterflies which entails opening the primary progressive butterfly farther thus creating a vacuum break. When one looks at a Bug or Bird Catcher for instance, all the butterflies are on a common shaft and as we close the butterflies to achieve an acceptable idle speed, these butterflies must remain slightly open. It is not uncommon for the engine pressure to bend the butterflies sucking them shut causing the engine to lose RPM. As the engine speed continues to slow, the pressure drops enough to allow the butterflies to pop back open where the engine regains RPM. This cycle continues creating a mechanically induced surge that cannot be eliminated. And in other instances, the butterflies can be completely sucked shut at the acceptable idle speed requiring extra foot pressure that pops the butterflies open resulting in an uncontrollable RPM surge. Regardless of which condition is experienced, throttle tip-in quality suffers dramatically. The vacuum break afforded by the open butterfly using the progressive linkage eliminates the sticking butterfly and the tip-in issues associated with it.

The other area where the BAU has an advantage over its Bug/Bird predecessor is the how the butterfly is shrouded in the bore. When you tip-in with a Bug/Bird, the bottom of the butterfly is immediately unshrouded allowing a moment of uncontrollable air to enter the hat. This phenomenon is dramatically reduced when the butterfly is still shrouded by the bore as with the BAU. Our Shot Gun hat also offers this superior design for excellent throttle tip-in control. These features make the BAU and the Shot Gun hat the best choice for larger cubic inch supercharged applications.

Supercharged EFI applications from Hilborn Fuel Injection are used successfully in all kinds of applications from street to drag race applications. We have even proven our designs in the real life torture test known as Hot Rod Drag Week. Our hands on experience tuning and racing these same systems allow us to design a system for your application whether running gas, E85/E98 or methanol and with either eight or sixteen injector nozzles. Feld Entertainment chose Hilborn Fuel Injection to help them design and implement a change from mechanical injection to EFI on their Monster Jam trucks (think Grave Digger). Successful dyno testing and field testing proved the concept allowing Feld to implement EFI on their fleet.

Let us work with you to custom design an EFI system for your supercharged application.

 Standard Features:

  • High quality heat-treated aluminum Enderle BAU3 casting with polished finish
  • Fully assembled with shaft, butterflies,  mounted TPS with connector and vacuum kit.
  • Polished 8 nozzle plate with dual -8 fuel rails (1.25 inches in height)
  • 3-11/16 butterflies with progressive linkage
  • 10.75 total height with the injector plate


  • -10 or -12 fuel rails
  • 16 nozzles
  • 4-3/8 butterflies
  • BAU1 casting 5 or 5-9/16 in. butterflies
  • Powder, ceramic or carbon fiber wrap finish options

Contact us to place an order or get a quote.

Sales Policies

Payment Policy: While we make every effort to fill and ship individual parts orders in a timely manner, complete injector kits and special orders may require more time due to the fact that each injector unit is built and flow tested to meet our customer’s individual engine specification and racing application. We accept all major credit cards or COD payments by certified funds. All shipments to foreign countries must be pre-paid.

Shipping Policy: 
Air shipments are available, however, unless otherwise specified, we will ship your order via United Parcel Service-ground. Orders sent to foreign countries can be shipped via United Parcel Service to most areas or by another specified Air Freight Forwarder (freight collect).

All retail prices referenced in the following pages are subject to change without notice. The current retail selling price at the time of shipment will apply to all orders. We cannot guarantee that all items referenced in the products catalog will continue to be available.

Return Authorization/Claims: 
Merchandise may be returned only within 30 days from the invoice date and only with pre-authorization. Refund, credit, repair, or exchange are given at our option after factory inspection. Returned items will be subject to a restocking fee of 10% of the list price. Returns must be sent freight pre-paid by the original purchaser and each item accompanied by the invoice number and purchase date. Merchandise returned COD, or after 30 days from the invoice date, will not be accepted. Claims for shortages must be made immediately upon receipt of your order.

Merchandise sent in for service and flow testing does not require a pre-authorization. Please include your name, address, and contact number along with any relevant specifications such as cubic inch of engine, type of fuel, type of racing, size of fuel pump etc…

: Our fuel injectors are manufactured strictly for use with high performance engines for racing and off-highway use only, and are therefore subject to the unusual stresses normally associated with this type of use. Since the operation of these engines is far in excess of the safe limits that are usually set for engines, breakage and failures are common, and are an accepted risk in racing. Also, the history of racing has always been one of trial and error by the users of this type of equipment. Therefore, because of the many unknown factors involved in experimentation, and because of the safe limits being exceeded by virtually every part in the engine, we do not offer a warranty of any kind on our equipment. It is purchased and used by the buyer at his own risk and with this understanding. If any of our parts become defective after purchase, the buyer assumes all cost of service or repair.

: Fuel Injection Engineering (FIE) is providing all information herein to familiarize potential customers with its’ products and services. Because racing is inherently dangerous, no representation of your safety is implied. To the extent permitted by law, this warranty is exclusive and in lieu of all other warranties or representations, whether expressed or implied, including any implied warranty of merchantability or fitness for a particular purpose. In no event will FIE be liable for special or consequential damages.

Finish Options

All HILBORN manifolds come standard with a clear anodize coating which provides the timeless nostalgia grey finish.

But customizing your HILBORN Injection to make it everything you’ve dreamed of is easy with our custom finish options. See below for a description of these options. Be sure to visit our finish options page to view colors and examples.

Polishing/Ceramic Clear Coating
Few finishes beat the glow of a highly polished manifold, making this is our number one finish option. Polishing can be mixed and matched with other finishes to provide a one of a kind manifold not soon forgotten.

Love the polished look, but not the constant upkeep required? Pair your polished manifold with our clear ceramic coating that eliminates the ongoing maintenance. Our clear ceramic is a high temperature, non- yellowing, scratch and impact resistant coating that eliminates the constant upkeep needed with bare aluminum. Once the manifold is polished, it receives a high temperature steam bath to remove any polishing residue before the ceramic finish is applied. Our ceramic clear will keep your manifold looking like new for years to come.

Ceramic Coating
Our ceramic coating is a high temperature, scratch and impact resistant coating, typically used on headers, that will protect your manifold from the bumps and bruises experienced by any application that is driven, raced or worked on frequently. Available in select colors and as a matte finish only, they are perfect for those looking for the best overall protection or to fit the more high tech looking engine bay that is trending today.

Powder Coating
For the most comprehensive color and texture options, powder coating is the best choice. With literally hundreds of colors available we’re sure you will find the perfect color for your special ride. Check out our powder coat color chart to see the numbers offerings!

Chromed ram tubes are the crowning touch to your HILBORN fuel injector and is the perfect maintenance free option that fits with any manifold finish.

Unfortunately we are unable to chrome the manifold itself.

Product Emissions Guide

Mechanical Fuel Injection Manifolds/Systems

All Mechanical based HILBORN Fuel Injection manifolds or systems are classified as “For Racing Use Only”  and are intended to be used on vehicles that are exclusively designated for racing use only. They are not legal for use on vehicles that are registered for street use.

Electronic Fuel Injection (EFI) Manifolds/Systems

All HILBORN EFI Manifolds or Systems can be classified for use on either:

  1. Pre-Pollution Controlled Vehicles (PPCV): Legal for use on pre-pollution controlled vehicles. They can be used on all vehicles that were manufactured before emissions control regulations were imposed. These vehicles are considered “uncontrolled vehicles.”

Uncontrolled vehicles are defined as…

1965 and older U.S. manufactured California Certified vehicles

1967 and older U.S. manufactured Federally Certified vehicles

1967 and older Foreign manufactured vehicles

  1. Engine Swap: Legal for use on engines that have been transplanted or swapped into an uncontrolled or pre-pollution controlled vehicle, as defined above. They are not legal for use on pollution controlled vehicles.

By agreeing to purchase, you acknowledge that your Company and all persons employed by the Company or you the purchaser and end user, understand the above notice regarding CARB-approved products, and the Company or yourself accepts responsibility for compliance with emission control regulations in the State of California. For more information please visit the CARB Aftermarket, Performance and Add-ons Parts Regulation page.

WARNING! This product can expose you to chemicals including lead and lead compounds which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information visit

WARNING! This product can expose you to chemicals including cadmium and cadmium compounds which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information visit

CA Proposition 65 Warning