They had to give you something for the extra $$$ !!

Old BG catalog .

Interesting looking at that catalog........by looking at their ratings, they show the annular boosters are a 100cfm reduction with the 1.590 sleeves, and a 205cfm reduction with the 1.562 sleeves.

I guess in fairness......at least on that page........ it's not listed as any kind of rating, but rather the "model".

yep them silver ones just didn't cut it on my combo. The black just seemed to make everything work better. didnt run any slower.

I'm not sure that I actually ran the silver sleeves on a motor.

I flowed that combo, and there wasn't any additional flow compared to the 1.562, but there was a reduction of booster signal.

This was actually on the predecessor to the Demon carbs..... The "Gold Claw".

On the dyno, the two best combos I played with on that carb were the 1.562/annular, and the 1.425/downleg.

I sold that carb to Brad, and iirc, his best ET's were using that 1.425/downleg combo.

I've had a reworked old school Holley 850 annular since 1991 that's always worked really good for me. Neither of those combos on the Claw were any "better"(although very close)than that old Holley, so I sold it off.

On the dyno... your "legacy" CFS 850 annular made close to 10 HP and a similar # increase in torque over the GC in 1.425/downleg config. That's what got me interested in trying the 1.562/annular config.

I couldn't get the 1.562/annular to run any quicker or faster on the track than the 1.425/downleg, and it didn't run nearly as nice on the street, either. I didn't have the patience, knowledge or opportunity to try it again before selling the annular boosters w/ the silver 1.590" sleeves. I do still have the black sleeves & downleg boosters, but will likely offer those for sale, too.

Speaking of the silver sleeves... when I bench-tested a bunch of carb bodies & GC sleeve & booster configs -- even using downleg boosters -- the silver 1.590" sleeve flowed LESS than the black 1.562" by 10-15 CFM IIRC, in addition to having less booster draw. My hypothesis is the transition into the large(r) venturi with the Claw / Demon entry form is too abrupt, which is why the venturi size increase doesn't translate into any flow increase.

I'd have to dig back into "the archives", but at some point BG upped the "model" of the 1.562/annular config to something "bigger", but I don't remember what at this point. BG's wet flow test #s they used to put on the back of the original Gold & Silver Claw brochures (I still have one of each) don't correlate to anything that makes sense to me, even today. Between BG and Holley, the "model" stopped relating to anything tied to venturi/booster/throttle size config years ago...

Most of our engines we run are 484 to 526, and I do not have the dyno experience others have, we have found the 4150 based annular carbs are always slower at the track. I think they flow a little less air. On the street they work great, but the track, the down leg ones are quicker. Especially with 50cc pumps.

Now we did dyno a 572 Hemi last year, and with a modified six pack of all things. That setup was within a dozen hp of a 4150 carb.....But on the street, it wouldn't even get out of the drive way. We learned, the dyno covers up a lot on the low end of the curve. That setup had a wicked stumble.

https://www.youtube.com/watch?v=WYw6RA-k5Bk

And no "billet" to be found on that old carb anywhere!!

My experience on my combo different tracks
Weather changes i dont have data
1050/4150 9.95 e85 60ft 1.34 tb 4500rpm
1050 dommy only 2 runs so far on it 10.07 e85 1.33 60ft tb4500 flat fuel curve
Stock stroke 440 .050 @ 3375#

Many have proven the good old Holley's to work well no doubt and I have worked a few like yourself but the Billet is just modern perfection in weight, consistency and looks. Not for everybody but drillin and tapping the old blocks is tedious and when you remove the well plugs and start gauging things, you'd see why Billet is better..........Billet wheels and components have taken over "stamping s" by a landslide and are truer by CNC design not castings w/core shift, flashing etc..........Needed for the average hot rodder, maybe not but like cams, cranks, rods etc, New tech has it's advantages and the only diss for some may be the price which really isn't that much more from a "custom" piece...............

I've been able to flow test a lot of bodies and boosters over the last few years, not all equally sized bodies (or boosters) are the same. Quick Fuel is at the top, Braswell may be up there but I have not had one of their 4150's to test. Right with it is the BLP billet. With Holley and Demon it depends on the body size. I have an RS Demon with 1.500 sleeves and it's as good or better than any. Go bigger with the sleeves and it goes away, the 1.590 actually flows and signals less. Holley has the Ultra 950 with a 1.600 venturi that has the same issue, I can get as much flow and better signal with a Quick Fuel 1.450 venturi 950. The problem is the sharp turn from the entrance to the venturi, gives it a ski jump affect compressing the airflow at the venturi point and creating turbulence. A properly designed venturi will allow flow to speed up at the venturi point with minimal change to the airflow, not the case for some of these. Someone didn't pay attention during the design of the bodies. Quick Fuel and the billets taper the correct angle before the venturi and don't suffer the issue.

As far as annular given the ability to size the body large enough/correctly they will always outperform a down leg. Atomization and distribution are far superior. I've had annular 4150 carbs perform better than a down leg and flow less, on 565 at over 800 HP. And there are also a lot of options with annulars, I have a QF body 780 for Comp Eliminator I put together, it dry flows over 1050 CFM with annulars. Just not your conventional annular...