I've been running a Holley 2100 ECC carb for the last 5 yrs, since I got it running pretty much. It is a larger-bore version of the Holley 94, so I figured I was getting some free HP... I've put up with its little issues, played with the jetting, but it just never seemed right no matter how much cleaning and tweaking I did. It also suffered from "PO-itis", some pieces didn't fit right, like the vac advance tube.

So I finally decided it was time to try something different, and bought a different 2100 off eBay for $40. Needed a couple of minor pieces that I already had, but was clean, and as I found out when I got it apart, well cared-for -- Vintage Speed power valve and gasket, for instance. Re-jetted it for altitude, threw in a new 6.5 PV for altitude, float setting was OK and a good needle, a quick spray with cleaner and threw it on. Twiddled with the idle screws, and hit the road...

OH MY GOSH! As soon as I tipped the throttle, I could see a HUGE difference!! For one thing, I can tell my vac advance is working where it never did before, and I swear it has at least 20 HP more in cruise range -- it flat out jumps at 40 mph! The big hill near me (6% grade) used to take all it had, now I can actually accelerate up it!

Moral of the story -- some carbs are just plain losers. If a good refreshing doesn't work -- GET RID OF IT!! There are plenty of good ones still out there! Best $40 I ever spent on it.

 

Thats great. Sounds like you got a great price on it also. Makes you wonder why you waited so long.

 

ok doke ross , is it a 3bolt like the 94 ? right hand linkage also ? i shouldn't even consider it as holley's and me as i have said don't seem to get along anymore , but ............ i gotta modify some things and get the linkage arrangement for left side etc. to run my 2 jet , so ........................... compare and see which is the lesser of two evils ................................ where's the guy with all the old holley's on here at .................

 

So just think how good it would run without a Holley!

 

Holley was originally a car manufacturer, that was supposedly superior to Ford. So Henry Ford bought the company in efforts to dismantle them, and ended up using their carburetors on Fords. And now you know the rest of the story.

Anywho, I once pulled a carb off a 70's 302, and put it on a 400, and it not only gave it better throttle response, it produced better mpg, too. Go figure, lol. Moral of the story: sometimes the sun shines on a dog's behind every now and then.

 

An example to illustrate this point would be; I trial fitted the 460 with C6 into my ’51 f1 frame that PO had an other make engine / trans in and it looks like (subject to Murphy of course) that the rear trans mount holes are dead on! Go figure. The sun is shinning on this fat old dog’s a$$.

 

I really didn't realize how bad it had gotten. Altitude really robs engines of power, like 20% at this altitude, so I assumed it was as good as it got.

Yep, it's a 3-bolt, just exactly the same as a 94 but 1-1/16" venturis vs 13/16" for the 94. (Another factoid: "94" stands for the venturi diameter, 13/16" = 0.940" ) Doesn't sound like a huge difference, but 1-1/16 bores gives it 27% more flow area.

My euphoria has been somewhat tempered as the day wore on; I drove it around and found it is flooding on hot re-starts, even some pretty cool re-starts. I think it may just need to be put in a shorter accelerator pump stroke hole.

Another thing for anyone running these (94's or 2100's); I found my old accel pump piston rubber had shrunk totally, so that the round brass it sits against on the accel pump rod was actually larger diameter -- in other words, the rubber was doing absolutely nothing. I had rebuilt it about 2 yrs ago with a Brand Name parts kit...

 

One of the biggest misconceptions of the carb era: A bigger carb will increase the HP/performance of any engine.
There's no "free lunch"!
An engine makes the most power when fed the correct ratio of fuel/air into the cylinder then that mix is fired at the right moment. With a carb this state only occurs at a small rpm band (due to the fixed size of everything controlling this, for all practical purposes) all other rpms are a comprimise. The engineers "tune" this rpm band to be in the most useful or most commonly used range.
Changing to a larger carb reduces the airflow speed (and increases fuel delivery if using OEM jetting) which can/does negatively affect the air/fuel ratio and fuel delivery to the cylinder as well as reduces the vacuum signal to the distributor, changing the timing.
If you happen to be real lucky and you haven't gone way overboard in carb size, this may still produce the ideal conditions at a slightly different (but narrower) point in the rpm band. If that happens to be the band you use most, then you may win, but more likely you are actually losing.

 

I recently put on a restored Autolite 4100 carb w 1.08 venturris .It's from Pony Carbs,a premium rebuilder that I'd seen praised by many guys on various Mustang/Galaxie forums.I got rid of my new Barry Grant Demon Jr,which I'd never been able to get dialed in, and which had always run poorly.
I gotta say,that's the single best thing I've ever done for my truck.If I didn't know it,I'd swear I am now driving a different vehicle.I did not,however,pay the high price from Pony - though I'd now do it in a heartbeat.I got it from Ebay,when a guy decided to go with a bigger engine and carb.I saved quite a bit.
Pony Carbs refurbishes Autolite carbs primarily,2100's/4100's and others,but also some of the older ones.They claim to make internal improvements to the original design,and correct design flaws.I can't argue that,I'm ignorant,I just know that I can't imagine a better dollar spent on a carburetor.No,I don't work for them.

 

Some truth there, but if it were completely true, no one would ever put a bigger carb, or multiple carbs, on an engine. There must be some benefit!

In this case the flat V8 has a carb sized totally for economy, not for power. I also have to flow 20% more air to get the same amount of oxygen into my engine as the same engine at sea level, and I have 2.5 psi less atmospheric pressure to push it into the engine. This larger carb compensates for that. If I were to put a 4-bbl on it, I'd likely be wasting my time without a cam change, porting, and increased compression ratio.