Here is an Ebay auction for a used C4OZ-6B068-E COBRA dual quad intake and carb setup by Ebay member "myrth_11" with a starting bid of $7,500.00:
Buckle up. I doubt you will find another like it any time soon. It took me fifteen years to find this. The ultimate Ford eye candy. If you have a 64-66 289 Cobra, GT 350, K- Code Mustang, Falcon, Comet or Fairlane, this is for you.
A SUPER RARE matched pair of Carter AFB 3258S & 3259S carburetors on a Original Cobra aluminum intake manifold. Both carbs are dated L5 which I believe is Dec 1965.
The intake appears to be in excellent condition and has a lovely patina. The correct and original Carter AFB carburetors were carefully restored by the experts at Chicago Carburetor in Eugene Oregon. They brought them back to perfect working condition. The bodies of the carburetors were left with their amazing patinas intact.
I am including all documentation from Chicago Carburetor so you know what was repaired/replaced and how much it cost and what EXACTLY you are getting for your winning bid.
They also replated the fuel log. It comes with fuel line and linkage. The intake is fitted with the proper Cobra heater cutoff fitting. For those who have Mustangs, etc. I’m including a standard Ford water heater fitting plus water neck.
It also comes with a pair of air cleaners. The filters and screens are proper Stelling & Helling’s that I have cut down from the larger 427 filters. They do not make the correct reproduction of the smaller 289 air cleaner assemblies.
The lids are the closest I could find to the originals. (If anyone has an original set for sale contact me). The lids come with the proper chrome acorn nuts.
It is unlikely if you will find a system like this anytime soon. You can always use aftermarket pieces, but nothing compares to this original over the counter Ford piece. What a way to improve the street cred of your original Cobra, Replica, K-Code Mustang, Falcon or Comet. Make your fellow Ford lovers envious over your impeccable taste and good fortune 
Put this on any 289 K Code and increase your cars originality and value. Judges and fans will drool with this amazing Factory Ford/Shelby combo. It’s not cheap, but it’s not overpriced either as it is a extremely rare early Ford performance piece of kit.
No more wasted years looking. No sending off parts to be refurbished. Everything has been done for you. It’s ready to slap on your SBF right now. ZERO buyers remorse on this one.
I’ve included a pic of the system my 331 Stroker K Code clone. No, motor is not included. It’s just for the glamour shot. I don’t want to sell this but I feel it needs a proper home. I’m sticking my stroker in a pickup and using this setup on a truck is a bit like putting lipstick on a pig. I’d rather see it on a Cobra, GT 350, Mustang or other appropriate Ford/Mercury vehicle.
***THIS LISTED ON MULTIPLE PLATFORMS. I WILL PULL FROM EBAY IF IT SELLS ELSEWHERE ***
If you have questions PLEASE contact me before bidding. No returns. I only ship to the lower 48 States. Shipping is free. I generally ship within (3) three business days. I ship UPS only. I will only ship after payment is posted on my account by eBay. If payment hasn’t been received in five calendar days I will repost and block from future bidding. No time for nonsense, I’m old 
Good luck !
Original 289 Cobra Dual Quad Intake and Matching Carter Carburetors | eBay
-Fred-