How to adjust the secondaries on an Edelbrock Thunder AVS?
I recently bought an '86 F150 with a swapped-in 351C which is topped with a Weiand X-celerator manifold and an Edelbrock Thunder AVS. The engine pulls real nice when I put my foot in it to kick it down, but off the line it's kinda sluggish.
Bottom line: What I want to do is adjust the secondaries to open earlier for more low-end power.
I know the Cleveland isn't the best for off-the-line torque, but I would still expect more power than this. The Thunder AVS has adjustable secondaries, which Edelbrock claims are "simple and quick" to adjust, but I didn't get the manual from the the guy I bought the truck off of, and I found the Edelbrock website to be of NO help at all.
OK, I own both a cleveland and a edelbrock carb but not the avs series. ON mine, by the throttle plate is a screw with a spring. Its thr opposite direction of the idle screw. Meaning you adjust the idle screw standing in front of the truck and the kickdown screw is adjusted as if you were standing at the back of the truck. Which is not possible so you stand on the drivers side of course. If you turn the screw in it will allow the throttle bracket to it it earlier and open the secondaries sooner. Let it out for it to open later.
screw is on drivers side
has a spring for tension
on throttle bracket assembly
screwed in for sooner opening
There's 2 screws that you need to adjust, and it is really easy. 1 is a Torx bit, I think a T-15, and the other is a flathead screw. I had one on my '77 that got stolen, so I haven't seen it a while. I know they are excellent carburetors, and they look nice too. You'll need to loosen the Torx screw to adjust the spring, which is done by turning the flathead screw. There's a spring wrapped around the butterfly for the secondary inlets, and that's what you're adjusting. I can't tell you which way you turn makes them open sooner or later because I've forgotten, but ultimately you just have to play with it until you get it just right, because every vehicle is so different. If you turn it one way and it gets even more sluggish, then obviously you've gone the wrong way.
John F. Daly III
'77 F-100 LWB, 100% Aftermarket 302-R.I.P. (Stolen)
'95 F-150 SWB, 300 I-6 sold @ 331,000 miles!
'96 F-150 SWB, 300 I-6, Eddie Bauer and 5 gears to row (current rig)
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