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I just put a 1972 318 engine with a Carter AFB 4 bbl carb into my 1971 Adventurer. After a bunch of troubleshooting and bringing it to a mopar mechanic I am being told I need a new carb or to rebuild this one. I'm looking at a few Edelbrock 1405 or 1406 4 bbl carbs, but how do I know if they will swap out with my Carter AFB and if the size/jetting will be right? Is there a compatibility chart or something somewhere? The other thought I have is if this carb is to big for my 318, is this possible? I have been finding out that a 71-72 318 with a 4bbl is kind of a rare breed. Any input would be greatly appreciated.

Steve

The reason that you feel as if an LA-318 with a
four barrel carb is "an rear breed' is from the
A-318 of 1962, there has never been an true
MoPar made 4 bbl LA-318.

The 4 bbl "Sq Bore" Intake Manifolds of the
LA-273 has all the correct Intake Manifold
to head port sizes of your LA-318. This unit
has never been sold/used by MoPar on a
LA-318.

All LA_340 or LA-360 Intake Manifolds will
bolt to your LA-318, but the Intake Manifold
to head port size is like fitting a 3/4 pipe
to a 1/2 inch hole.

In the Eighties MoPar sold/used some LA-360
Intake Manifolds on some LA-318's.

Now to the carb question.
Due to the cube size of your engine ( 318 )
the best carb to use is one no larger than
500-550 CFM's max. Any larger CFM is wasting
fuel and getting a lower MPG .

To rebuild is cheaper than to replace.

Rodger & Gabby
COS

1405 and 1406 are the same "cfm"-600,the 1406 is made to run leaner by 2% (according to an edelbrock tech.)with the right combo of jets and rods im sure you could make either one work good on your 318.I recently put a 360 4 barrel intake on a '67 318,i used a quadrajet i had laying around,it runs way better than it did with the 2 barrel.
(After edelbrock bought Carter,they kept building the Carters the way they were but just put the edelbrock name on them,i think).

Hello All

Here is an aide for all to use if they are thinking
about what size of carb should I use with how
truely use my engine.

http://www.gtsparkplugs.com/CarbCFMCalc.html

Rodger & Gabby
COS

Thanks all for the input. Since I was about to purchase a used carb to replace mine, I decided thatI would first go for broke and remove mine to investigate. I am quite green when it comes to mechanics, and even greener when it comes to a carburator. I think I mentioned earlier that the reason it was needing replacing was because of my gas tank sediment that got into the carb. So anyway I removed it and with a can of carb cleaner, some ether, and a air compressor to blow it out, I was able to clean it up wuite nicely and I'll be damned the thing runs great. It could probably use a rebuild kit at some pont in the near future, but for now the problem is solved and the Adventurer is on the road again. Thanks for you tips and input. I'm finding that the amount of info that everyone offers is really valuable.

you got off lucky with a cheap quick fix. its amazing what a little cleaning will do sometimes. I used to have an 83 d150 that was a personal play toy( she would scoot) that had a slightly warmed over 318 auto in it. it was a combo vehicle , i used for both personal fun, but also towed loads as heavy as 8000 lb plus with, delivering machinery i had built or rebuilt. When i bought it i had a holley 650 or 750 on it, that thing would run like a raped ape. I wasnt much off the line( 3.23 gears) . but once she was rolling she was quick ( that old truck embarrassed a lot of so called musclecars, with my little old 318). After rebuilding the holley a couple times, and having problems with leaks and accelator pump problems, i decided to try the Edelbrock as it was similar to the old Carters. I bought the sping and needle kit to fine tune it as well. After trying numerous setups, i finally found a combo that gave good performance, but much better mileage than the holley did( probably3mpg) it didnt run quite as good as the holley , but still had enought to embarras my buddies once in a while. I always wanted to put lower rear end gears in it, and put an overdrive tranny in. I think it would have been great, but truck was totalled my a college student who hit me head on in just the wrong place.

Darn, i miss that truck.

duke21