Starfury

Setting aside the previous post for a minute, neither would be recommended. The problem is the 600CFM 1406.

Your engine, even at 100% volumetric efficiency @ 5500RPM, will only pull 460CFM. In the real world, and depending on the condition of your engine, 70-75% VE might be more realistic, and I don't know that I'd want the motor spinning above 5k without some rotating assembly balancing and dramatic valvetrain upgrades.

So let's call this 75% VE @ 5000rpm, to be optimistic. That leaves us with a 314CFM requirement. You can over-carb a little without causing too many problems, but going too big just reduces throttle response and driveability. You don't force air through an engine (without a supercharger), you pull it through; so over-carbing doesn't get you increased airflow.

Ideally, a 400-450CFM carb would suit your needs just fine. An Autolite 4100 (w/ 1.08 venturis) flows just above this, but has annular boosters which will help increase fuel atomization and throttle response.

A 500CFM Edelbrock is about as big as I'd recommend going. Edelbrocks, while simple to adjust, are not terribly adjustable, and it can be hard to tune out small hesitation and throttle response problems when varying from their ideal application. I'm quite familiar with this problem, as I have a 1406 on my aggressive 331 and I can't quite get it tuned perfectly.

My recommendations would be:
1) Your current 2100 and stock intake
2) An Autolite 4100 w/Performer 289 or Weiand Action Plus
3) An Edelbrock 500CFM model w/Performer 289 or Weiand Action Plus

MtnMustang

Starfury is spot on.

I did a lot of research when I did an intake and carb swap and all the math pointed to approximately 450 CFM for a primarily stock 289. While I still think I should have spent a little more for a Holley, I did get an Edelbrock 500 with a Edelbrock Performer intake. Even then I had to go one size smaller than the recommended jet sizes for my application and altitude. So for runs great, but as mentioned there are some slight little hesitation off the line with the Edelbrock carb that I know I can tweek out in a Holley based on how their accelerator pump is adjustable. I bought the Edelbrock new and it was a lot cheaper than the correct Holley. I did have to buy a kickdown lever adapter with the Edelbrock where with a Holley it would not be needed.

If you have a 65 66 and early 67 you will need different kickdown adapter than later 67 and newer.

Older #8011 newer or with AOD #1483

I also had to spend more time adjusting the kickdown lever on transmission than I expected when converting to the Edelbrock. Just some slight differences in the fulcrum of the throttle linkage etc that made me spend a little more time than I expected. Works like a champ though.

Also some of the intake bolt kits are actually too short for 289 and early 302s. Edelbrock's chrome kit is for sure. Double check them before you get the gasket sealer etc on and you have to make a quick run to the store for longer bolts. Use a Grade 5 or better even though you are not torquing them down that much, the threads will strip otherwise. Also keep in mind the Ford Windsor blocks have some slight variances with the intake manifold gaskets, which means you may need to trim one or more in the water passage areas. Just pay attention to the original and be sure you do not trim the gasket over the top of the engine with it opened up and accidentally let the piece fall into the block via the distributor opening. Yep happened once and had to pull the oil pan.

barnett468

street warrior is better for your app.

the 500 cfm is way too small for a 331 so you will need to get another carb when you do that.

your 2100 likely stalls because the float level is too high or their is debris in the idle circuit . you can remove the nozzles then spray a bunch of carb or brake cleaner in the 2 holes on each side of the center hole in the carb body with the long nozzle . then spray every hole in the nozzle.

put a small clear plastic fuel filter just before the fuel pump.

a holley style carb is far more easy to tune.

use the steel reinforced fel-pro intake gaskets.

if you live where it is warm, block off the heat cross over.

set your timing curve so it is optimal for your setup.
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Stangalang15

I know this is an old thread but wanted to chime in on your issue. Dont know if you ever replaced your carb and intake but I had the same issue with my 68 turning off on stops. I had to place it in park while I waited at red lights until my uncle whos a mechanic told me it sounded like the brake booster was letting too much "air" into my engine. Replaced it and problem solved. This was back in the late 90's/ early 2000's. Im in the process of getting my 68 back up and running and looking for info since I bought a 1406 a while back for $75 and an intake from Summit, but now just thinking of selling them and throwing my 2bbl intake and 2100 back on since they never gave me issues, but hopefully this info helps someone in the future.