The recent post about superchargers and carb cfm's got me thinking about what sort of carbs I want to run on mine. 4-71'd flathead, so I can't really overcarb it (and I'd rather have way too much flow than not enough). Of course there's the old standbys, Strombergs and 94's, but compared to the later 2 barrels they're flow numbers seem a little low and I know that the blower will tame down bigger carbs, but the 400ish cfm of a pair of early Holleys just seems a bit low to me (unless I'm TOTALLY missing something about blower carbs and flow rates). I see lots of mention about the Rochester 2GC's, which are high on my consideration list since they outflow the earlier models and are easier to come by, but frankly I don't know ANYTHING about them to even begin to know where to look for them to get a matched pair or what cfm's are available, NEVER had a GM or even physically touched a Rochester 2 barrel. Something I NEVER hear anything mentioned about are the Autolite 2100's... I know some of them can really flow, a pair flowing at least 700 cfm is fairly easy to come by, and the posibility exists to get even over 800 cfm. They're also easy to match size-wise as they're stamped right on the side. In the other blower thread, it was recommended to use at least 50%-100% more carb on a blower motor than a NA engine; of course plenty of flatheads use a pair of 94's flowing in the 300-400cfm range, so the 700-800cfm range of the Autolites would achieve that and bet really work well on my engine. Are there any issues with the 2 pot Autolites? I know the 4300's are pretty well liked by muscle car guys, how good a runner are the 2100's? I figure if I can match a high-flow pair fairly easily (since the venturi size is stamped right there) and strip them down of all the random shit bolted to them to get them down to the bare bones carb (and probably mill down the choke towers while I'm at it). All the ones I've seen use the basic 4bbl air cleaner base, so that'd be a piece of cake to deal with. Why does it seem that no one uses them on early motors? What year did Ford release them, is it that they came out too late to be considered a "traditional" styled carb? I'm about 75% certain I'll be running a Gilmer drive since I found on Roadrunner Engineering's website a crank pulley that a blower pulley can be bolted to (which was at this point my first biggest stumbling block) at a great price (at least I think so, at $80). That really will put my flatty in the mid- to later 50's era, were the Autolites around then? I mean, they aren't the sexiest lookin' carb, but strip all the crap off them and they look like a get down to business, no-frills sorta deal. I've had lots of Ford motors that WERE 2100 or 2300 equipped, but by the time they reached my hands they were long gone (or I had a 4 barrel intake that I immediately swapped to), so I know nothing of their performance or tunability. Are there any shortcomings when it comes to them? I just wonder why I never hear tell of them, since we're all 2 barrel sorta guys and they're some big flowin' 2 barrels.
I can't answer your question, but they are popular carbs with the Jeep crowd. A few years ago I sold several on ebay for a decent price, some working and some that looked like they hadn't ran in decades. I try to keep an eye out for them to resell, but they don't turn up cheap like they used to. Not much on them, so easy to rebuild.
They are a great carb...until the shaft wears out and starts sucking air. The 4100 is also a great carb. I have used tons of them, had very little problems with them.
2100 are a good carb and real easy to over haul, however the old flatty manifolds wont allow them to be a bolt on. The 94 is also a good choice among the flattys and are one of the best "older" applications using gas. The 97's are a favorite among the alcohol users and are easy to enlarge the jets and drill out a couple of ports for use of alcohol. I like the 94's better for the gasoline over the 97's and they flow more cfm so for bolt on carbs this is basically how I evaluate them.
They work well, and are simple to rebuild. Also they lack the gasket set up that Holley uses, So you don't dump the contents of the bowl, when you open one up.
Well, I hope I have as good a luck with them as you guys have seemed to have... I picked up a good rebuildable core with the 1.23" venturi size (the biggest, 358cfm) for $14.99 and am waiting on another one for the same price to go off in a few days. They're a 68 and 69, so they're later (and not exactly the same) but by the time I unbolt all the unnecessary crap, cut down the choke tower and mounts, they'll be identical and will look just like the early ones. From looking around, it looks like Ford started with them in 1957, which is just about perfect for my era motor-build (the last of the flathead diehards in the mid-50's ). I think they'll be really nice, as opposed to about 350cfm with a pair of 94's, I'm looking at 716cfm, so the blower should be able to get the air it wants for sure. All and all I'm pretty pleased with my decision (thanks fellas), sorta traditional and not something totally outta left field, but a bit different. In all my searching, I didn't find anyone that had anything bad to say about them (at least past bellyaching about things that just signified a rebuild was in order). Just for future searches, here's some info I found on them: From a Hemmings article: Jon Enyeart at Pony Carburetors explains that their modification is superior to the original Holley system by utilizing Autolite 2100 carbs. "The 2100 carburetors use an annular fuel discharge design," says Enyeart. "Holley, Carter and Rochester carbs are analogous to watering your lawn with water pouring out of the end of a hose. The design of the Autolite 2100--which was patented by FoMoCo in 1957--atomizes fuel more effectively than any other carburetor in history." "The Autolites blow away anything Holley ever made." CarTech Autobooks, Induction Systems: Like the earlier Autolite and Motorcraft 2100 carburetor, the late-model 2150 is a fiercely reliable carburetor due to its simple design. MRE Books: The Autolite 2100 two-barrel carburetor was specific to each application, with no two applications having the same Ford part number. Identification of these carburetors is straightforward. Throttle bore size is your first visual clue. For example, a Autolite 2100 big-block carburetor has much larger throttle bores than 2100s designed for the 221 and 260 engines. So the big-block 2100 carburetors throttle plates will not open to full capacity if installed on the 221/260 in error. Likewise, a small-block carburetor installed on a big-block in error will dramatically reduce performance. The type of carburetor is determined by the venturi diameter size which is cast in the left-hand (drivers) side of the carburetor body beginning in the 1960 model year. What you can expect to see are numbers like .98, 1.01, 1.02, 1.14, 1.23. This is the venturi diameter in inches. The higher the number, the larger the venturi diameter in inches. The 221ci small-block was fitted with eight possible 2100 types, all with .98-inch diameter venturis (190cfm ). The 260 and 289ci engines were fitted with 2100 carburetors with 1.01 (245cfm ) and 1.02-inch (240cfm) diameter venturis, depending upon application. Venturi size originally depended upon transmission, vehicle application and original sales district. California emissions carburetors, for example, were jetted differently. This was also true for vehicles delivered to high elevation areas like Denver. For 1964, the 289 received a larger throttle bore 2100 with 1.14-inch (300cfm ) venturis. This gave the 289 improved low-end torque.
The Jalopy Journal
