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Discussion Starter #1

I recently put in a new carburetor (replaced a Carter 9635 with an equivalent Edlebrock 1906 AVS2) in the '65 GTO. The engine is a '389 out of a '66.
Car's running well and I am enjoying the new annular flow from the primary boosters as it drives/shifts very smooth.

My questions for those with a similar setup or in the know:

1. Car has a three speed automatic transmission and my vacuum tube is somewhat flopping around in the back of the engine. Was the metal portion of the tube ever attached to anything in the original design or just left dangling. Screenshot is attached.

2. When I give the car throttle, at a very specific point of the main jets opening I am hearing a squeaking sound (similar to a belt squeak). The best way to describe is if you consider the throttle 0 to 10 with 0 being untouched and 10 being floored, it happens when I get to 3. If step on the throttle and go to any number (other than 3) I don't hear the squeaky sound. I can confirm it happens in idle and I can confirm it's definitely coming from inside the carburetor. I've taken the air cleaner off and when you stand over and manually press the throttle with your finger you can hear it coming from inside. I am thinking that maybe the gasket is not seated correctly or a bit is sticking out inside like the reed of a clarinet and only causing the sound at a specific vibration but I cannot see anything. Any method to check for a gasket leak that's not happening at idle?

3. Vacuum on front/back of Edlebrock. I reversed the vacuum lines and stuck the brake booster on the front and the PVC on the back. What am I really missing by doing this setup?

4. Kick-down cable attached or detached?
The car is a driver for the wife and she's not a lead foot. I don't think she really cares if the car downshifts to pass as she's not driving more than 55 anyway. I currently have it connected and working but I am contemplating removing it to keep me from driving like a bat out of hell and making the wife more comfortable. Forgive the bolt as the edlebrock throttle stud did not fit the Pontiac cable. Ideas on if I should just unhook the kick-down cable?



Super Moderator
5,741 Posts
I'm not sure what was original, but if you want to secure the vacuum line to the modulator there's a bolt hole on the back side of the head that you can use. On my 69 it does "double duty" - I use it to secure the top of the dipstick tube and the vacuum line.

If you're sure the squeak is coming from the carb, your guess about it being a gasket edge is probably correct. "Something" is vibrating and resonating, or there's an air/vacuum leak somewhere that's causing a whistle.

Vacuum lines to front or back: You're not missing anything. Manifold vacuum is manifold vacuum and the source doesn't matter --- with one provision: Carburetors (most, but not all) have provisions for both ported and unported vacuum sources. Ported is generally (but not always) used as the source for the distributor vacuum advance because it doesn't begin to operate until the throttle is opened beyond idle, because the source for it is located above the throttle blades. The "others" are below the blades so they "see" vacuum all the time. Your carb doc should tell you which source(s) are which.

Kickdown: - that's really up to you.


64-67 Expert
8,561 Posts
I'd simply adjust the kickdown cable so that it kicks down closer to wide open throttle. That way, it'll only downshift when you need it to....like to get out of somebody's way to avoid getting hit. Always good to have the option of a fast exit.
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