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.
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
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!
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.
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.
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.
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.
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.
To The TESTING ==>