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Discussion Starter · #1 ·
After finishing another project I'm finally back to working on the car that I inherited
from my Mother. This 1972 cougar XR-7 Convertible has a 351 Cobra Jet. Car has 26K original miles on the clock.
This engine has an Autolite 4300 D carburator. This carb is like a GM Quadrajet in that it has huge secondaries. I'm looking for some ideas and what to replace it with. I prefere to keep the original manifold if possible.
Any input would be appreciated.
 

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The 4300D flange is unique. Your choices, without any kind of adapter plate, are limited to another 4300D or maybe a 4350.

 

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The 4300D flange is unique. Your choices, without any kind of adapter plate, are limited to another 4300D or maybe a 4350.

Woodchuck called it... If you want to put it back to the way it was purchased, stick with a like model carb. If you want to get almost unlimited options you need to run an adapter plate or replace that spread bore intake for a standard flange 4v accepting almost every option you could want.
 

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As Woodchuck noted, nobody makes a direct bolt on replacement for the 4300D series. Trans-dapt makes an adapter plate, it allows you to run a standard square bore carburetor on the CJ intake.


My choice for a 351CJ would be the Summit 750 vacuum secondary.


No matter what you get, you will need to tune the carburetor to the engine and make adjustments to the fuel line, trans linkage etc.
 

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Discussion Starter · #5 ·
An adapter plate is pretty much out of the question. With the stock carb and air cleaner there is very little hood clearance.
 

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Discussion Starter · #6 ·
I might add that this was a California car and I remember when my parents bought the car new they had several warranty claims for carburetor problems. Even my father who was a mechanic could never get the car to run right.
 

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I might add that this was a California car and I remember when my parents bought the car new they had several warranty claims for carburetor problems. Even my father who was a mechanic could never get the car to run right.
Ford could never get the carb right, neither could thousands of mechanics.

If an adapter is out of the question, then I suggest you locate a factory 70-71 M-code square bore intake and swap it for the Q-code piece. Nobody but you will know they've been swapped, as they look identical on the exterior, have the same vacuum ports etc. Shouldn't be hard to locate one for $100 or less.
 

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Discussion Starter · #8 ·
I have thought about an intake swap and looking at the Summit carb I wonder have difficult it would be at adapt the throttle and trans kick down linkage linkage?
 

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I have thought about an intake swap and looking at the Summit carb I wonder have difficult it would be at adapt the throttle and trans kick down linkage linkage?
You have a great car and engine combo, but has a ball and chain attached to it with that intake and carb setup.
 

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I learned something new today. I did not know that there was a "351" Cobra Jet. I had a friend with a 73 Mustang having a 351 with 4 bbl carb and later when it was torn down we discovered it had 4 bolt mains. I wonder if this was a Q code 351 CJ or a low performance 351 that just happened to get a 4 bolt block that was left over from previous years production runs.
 

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I learned something new today. I did not know that there was a "351" Cobra Jet. I had a friend with a 73 Mustang having a 351 with 4 bbl carb and later when it was torn down we discovered it had 4 bolt mains. I wonder if this was a Q code 351 CJ or a low performance 351 that just happened to get a 4 bolt block that was left over from previous years production runs.
Its the BOSS 351 little brother... Awesome rare set up!
 

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Cougar72, the 4300 carbs were bad, all of them. They are prone to leaking fuel, lots of older Fords, Mercs and Lincolns were scrapped after engine fires because of this carb. The 4300D is UNIQUELY bad, with its spreadbore, but not normal spreabore, araingement. You should put the intake and carb on a shelf, and get a BlueThunder intake and the Summit 750 carb. LSG
 

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Discussion Starter · #14 ·
I have the original widow sticker that came on the car . Under options it has "351 Cobra Jet".
If Im going to change the manifold I'm look at that Edlebrock or the Blue Thunder.
 

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I learned something new today. I did not know that there was a "351" Cobra Jet. I had a friend with a 73 Mustang having a 351 with 4 bbl carb and later when it was torn down we discovered it had 4 bolt mains. I wonder if this was a Q code 351 CJ or a low performance 351 that just happened to get a 4 bolt block that was left over from previous years production runs.
351 Cobra Jet was introduced late in the 71 model year with the Q code VIN. It carried through 1974 in the intermediates, 73 in the Mustang and Cougar. Ford marketed it differently depending on the car it was in. Some were just 351-4V, others as 351CJ. Either way, it was a good setup for the times and if the carb hadn't been such a POS, they'd have been much more respected.

If Im going to change the manifold I'm look at that Edlebrock or the Blue Thunder.
The Edelbrock Performer for the 4V heads is a good choice, if you can find one. They're out of stock everywhere. The Blue Thunder is the best of the best, but it does raise the carburetor up a bit. You should verify how much hood clearance you actually have if you go this way.
 

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Cougar, what timing set does this engine have currently ? I ask because you said the car never really ran right, and yeah, the 4300D carbs aren't well thought of. BUT, in an effort to reduce CO emmissions Ford retarded the camshft by about 4~6 degrees in the '72 models. Was done by the timing gears being made differently. The cars of that era ran like crap. We USED TO sell 2 different timing sets, emission controlled and non-emission controlled. If you knew what Ford had done, and you understood the problem, you got a timing chain and gears for the '70-'71 model and swapped them out. Dealers and garages made TONS of money fixing this issue. Now, most of those 'emission control' timing sets are long gone,.....but you never know. LSG
 

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Check around and send THAT carb out to a pro rebuilder.
 

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Funny, not denying that issues existed (apparently they did), but my two Q-code CJ's run like they're fuel-injected. A '73 Cougar XR7 convertible with 500 original miles, and a '73 Gran Torino Sport 4-speed with 28K original miles. Both bone-stock and never apart.

Now, I won't say that they're exactly "barn-burners" in the performance department. But the carb tuning is spot on, smooth idles, smooth acceleration and no hesitations.
 

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Discussion Starter · #20 ·
bossnine, This car is completely stock and has not been driven for 35 years. It was stored covered in my mother's garage. So both your cars have the 4300D carbs and you have no issues?

The timing gears are next on the list as I believe this engine may have the nylon cam gear. Even with the low low mileage on this engine Im sure time has taken its toll on the nylon gear. I'll check the camshaft timing then.
 
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