2100 carb question

[64.5 TX Stang]

Is there a difference between the 2100 carbs used on the small block fords and the big block fords? I would assume that the latter will be larger? Is one better than the other for our application? Does anybody know what the approximate cfm of the cars are, if in fact they are different. Many thanks, Andrew

 

[Hot 6t Falcon]

The motorcrafts are easily distinguishable. There is a cast-on number under the pump rod. See picture.

The number indicates the Venturi diameter. The most common number on a small V/8 is "1.08" Big V/8's often have "1.21".

Remember, that too large is just as bad as too small for street use. An engine can use a larger carb for all-out racing than would be used for daily driving. On an otherwise "stock" 200ci, I'd use a 1.08. If your 200 has a cam, headers, and electronic ignition, added compression then use a 1.21.

Some common Autolite two-barrel sizes:
Cast # CFM
.98 190
1.01 245 (all of these are either
1.02 240 1.42 or 1.55â€￾ throttle
1.08 287 bores)
1.14 300

1.21 351
1.23 356 (these are 1.68â€￾ throttle
1.33 424 bores)
(This information is taken directly from our book.)

 

[64.5 TX Stang]

Thank you for the tips, I have a 1.14, and a 1.21. However the 1.21 has an anti stall dashpot on the accelerator linkage, meaning it was probably from an automatic car. I have a standard, can I just remove this, and is this carb jetted differently than a carb from a manual setup. Also is the 2100 a good carb for this or should I look for a holley 5200?

 

[Hot 6t Falcon]

The 2100 is a good carb.

It has a few tuning quirks. Normally on a carb, you would turn out the air mixture screws about 1 1/2 to 2 turns. We've found that they need to be out 3 1/2 to 4 turns. You'll have to play with it a bit - but you'd have to play with the Holley too.

When you look at a 2100 carb rebuild spec sheet, you'll see that they have several different float level settings depending on the factory application. I use the highest factory float setting on my 200. David (brother) uses a middle of the road setting for his 250. Like I say, you'll have to play a bit to match your application - but that's the gratifying part.

There's no difference between the auto and the std. carbs - other than some added stuff like the dashpot. However, would avoid the later 2100 that had electronis sensors - If its got wires coming out of it anywhere (other than the choke), find a carb without wires.

Look at both of the carb jets sizes. If they are different, try playing with them as you fine tune the carb.

PS At cruise night, when I pop my hood, my carb is ALWAYS a 500 cfm two barrel. It's better to exaggerate on cruise nights, than to have a foul running car the rest of the week.