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Holley Truck Avenger Off-Road Carb
& Power Shot Air Filter

By Jack Brinks

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So the Holley Truck Avenger looks great, but how does it perform? Before finding out, we've got to install it. In my case, removal of the Quadra-Jet was more complicated than the installation of the Truck Avenger. Since no one makes a spread-bore intake manifold for an AMC V-8, installation requires an adapter, which is shown in the photo comparing the two carburetors.

Holley Truck Avenger Holley Truck Avenger

Once the old carburetor is removed, stuff a clean rag down the intake to catch gasket material you'll have to remove. If necessary, install new carburetor studs carefully, especially if your intake is aluminum. Install two nuts on a stud, tighten against each other, and snug them down.

Holley Truck Avenger

For the sake of safety and ease of installation, make certain your throttle linkage will hook up properly. To properly install my AMC throttle cable to the Holley, I used their Throttle Extension Lever, PN 20-7. Holley makes several different adapters as shown in the installation instructions, which you should take the time to read carefully. Although the Truck Avenger is a "universal" carburetor, there are a few applications that it won't fit, so take a few minutes and read before you bolt it on. If you still have questions, call Holley Technical Service toll-free at 1-888-Holley5 (1-888-465-5395). I found that these people know their stuff, so don't hesitate to call them!

Holley Truck Avenger

I drilled an extra hole in the throttle extension lever to hook up my hand throttle cable, which is something that I just can't live without. Bolt the extension to the carburetor, and using the supplied base gasket, set the Truck Avenger on the intake. Install the nuts on the studs and tighten carefully in a criss-cross pattern until you reach 60-80 inch pounds. If you don't have an inch pound torque wrench, that means snug them down with a small wrench. Over-tightening could warp or crack the throttle body, so don't get carried away.

Next, hook up the throttle cable using the ball connector from the original carburetor (Holley also makes various sizes of these), making certain that there is no interference during throttle opening.

Next, install the throttle return spring. Hook up fuel, PCV, and vacuum lines as needed, and don't forget to block off unused vacuum ports. The electric choke must have an ignition-on 12 volts to operate properly. I simply ran a wire from my starter solenoid for this. I hooked up my hand throttle using a part that I had taken off an old Quadra-Jet, two large fender washers, and a circle clip. It spaced the cable away from the throttle and keeps it from interfering in any way.

Holley Truck Avenger

Ok, now we're just about ready to fire it up, but just to be sure, check everything one more time. Then, crank the engine for 10 to 15 seconds to fill the bowls with gas. Stop cranking, hit the accelerator pedal once or twice to allow the accelerator pump to squirt some gas into the intake, and start it up! In my case, the engine started right away, and the electric choke worked perfectly, bringing the fast idle speed up to a factory pre-set 1,600 RPM. After a short time, I tapped the pedal and the RPM came down as designed. After a minute or so, the idle came down to around 1,000 RPM. I then set the idle speed to 700 RPM by simply turning the curb idle speed screw.

At this point I began to experience a problem. The "idle" speed would intermittently stick at close to 2,000 RPM, getting worse as the engine got hotter. After some "fussin' and cussin'" I removed the carburetor for closer inspection. The culprit was a bent fast idle cam arm that was contacting the choke housing, causing the throttle to jam slightly. The arm is above the red fast idle cam seen in the photo. While it is possible it could have happened in shipping, the most likely cause of this was my handling of the carburetor while setting up for the pictures you see here. Either way, after a little "adjustment" everything worked just fine.

Holley Truck Avenger

If you read Holley's instructions, about the only adjustment you'll need to make is to set the idle speed to manufacturer's specifications, and that may well be true for most engines. While the idle mixture was fairly close, it was running a bit too lean. This, I'm sure, has something to do with engine size and the fact that it has 10 to 1 pistons and an Edelbrock Performer cam and intake. Currently, the Truck Avenger is only available in a 670 CFM (Cubic Feet/Minute) size, which is a little small for my engine. But since I usually do mostly rockcrawling and hill-climbs that require mainly low speed torque and response, I felt it would work.

To top off my new carburetor, I installed a new Holley Power Shot Air Cleaner element to replace one that had been slightly damaged by battery acid in a roll-over. (I installed an Optima gel battery some time ago to keep that from happening again). This air cleaner features a life-time warranty and can be cleaned and re-oiled as necessary depending on your driving habits. It is also said to flow 5% more air than its competition. With the dust and dirt normally associated with off-roading, a filter like this is the only way to go.

Holley Truck Avenger Holley Truck Avenger


On To The TESTING ==>

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