Rookie question

[beached 1]

What is the difference between a Annular carb and a regular one.
I'm getting a bigger carb this winter and want to make the right choice..
This on a 466 BBF, 525 HP (give or take)
Thanks,
850 Annular Mighty Demon
Part # 5563020GC
Part # 5563020BC
Well-prepared 440 - 509
cid engines
--------------------------------------------------------------------------------
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850 Mighty Demon
Part # 5563010GC
Part # 5563010BC
Well-prepared 480 - 540
cid engines
Annular
http://static.summitracing.com/global/images/prod/large/gpt-5563020gc.jpg
non annular?
http://static.summitracing.com/global/images/prod/large/gpt-5563010gc.jpg

[Mohavekid]

Good question, I've always wondered what the annular boosters are supposed to do and why they're supposed to be better.

[Craig]

Annular boosters help when you use a big carb on a smaller motor. They increase signal stregth and fuel atomization, enabling a smaller jet size and the ability to run a larger cfm carb on a smaller displacement engine, giving the low-end feel of a 600 cfm carb with the top end flow of an 850.
Craig

[Infomaniac]

Those boosters in the center of the venturis are either annular or down leg.
The bottom one down leg discharges the fuel from one hole in the booster.
The top one annular has holes around the diameter of the booster and discharges fuel annularly.
:) :)

[Racing Ray]

http://www.highperformancecars.com/collinsracing/boosters.gif
Just like Info says. Example of a straight leg booster and down leg booster. Contained inside is a cone that has the orfices drilled or slotted.

[beached 1]

Thanks for the replies!
I'm having gret results with my Speed Demon 750, but I think I need just a little more CFM. I guess I'll go with the Annular

[LakesOnly]

Originally posted by beached 1
I'm having gret results with my Speed Demon 750, but I think I need just a little more CFM. I guess I'll go with the Annular
Beached,
If you have a 525HP 466 Ford, then I think your motor can handle way more than a 750 Demon carb. I have two 660'2 on my 466 and technically it could handle more.
If you want just one carb, look at at least an 850.
LO

[beached 1]

Originally posted by LakesOnly
Beached,
If you have a 525HP 466 Ford, then I think your motor can handle way more than a 750 Demon carb. I have two 660'2 on my 466 and technically it could handle more.
If you want just one carb, look at at least an 850.
LO
Thanks for the reply LO. I really respect your opinion. What might you suggest I should go with CFM wise? My heads are D0VEs, exhaust ports were cleaned up (humps and bunps taken out), but not ported. Intakes were cleaned up a little as well, but same size as stock.
Like I say at top of this thread, I am a rookie at this. Is it true that Demon's technically flow more than a stock Holley? I was told that, "Demons flow their carbs wet". In other words, if I go with a Demon 850 isn't it similar to about a 900 cfm type of holley? This may be why my Demon 750 feels pretty good to me but does seem like it's a little choked off on the top end. I am currently running a Wieand Stealth (one of my problems I know) with a Speed Demon 750 mec secondaries. I am changing this to a (line ported and matched with my heads) Offy Port-O-Sonic mid rise single plane and a bigger carb. I guess I'm afraid of going too big. According to the Barry Grant application chart, the Annular Mighty Demon 850 looks like it would suit me pretty good. But you think I need bigger, please let me know.
Thanks,

[LakesOnly]

Originally posted by beached 1
My heads are D0VEs, exhaust ports were cleaned up (humps and bunps taken out), but not ported. Intakes were cleaned up a little as well, but same size as stock.
According to the Barry Grant application chart, the Annular Mighty Demon 850 looks like it would suit me pretty good. But you think I need bigger, please let me know.
The D0VE heads are fantastic high compression passenger car heads. Unfotunately, the exhaust ports are heavily restricted (as is most all passenger car 429/460 BBF stuff). Believe it or not, stock D0VE exhaust flow maxes out at a measely 135 cfm from 600-lift on up. Proper porting can net almost an additiional 100 cfm (220-230 cfm on the exhaust). This is almost as good as ported Super Cobrta Jet exhaust (240+cfm).
Back to your case: Porting of the intake and especially exhaust valve pockets is where you will find most of your increased flow. But porting this area incorrectly can hurt more than help.
The Annualar Mighty Demon will suit your motor just fine cfm-wise. I bet you'll be happy with that carburetor. Next time your heads are off, get them to a well-known BBF head porting specialist and you can adjust your carb to deliver even more power from your engine, and also have the option of going even bigger--2-4 tunnel ram if you want.
Just my .02,
LO
p.s.: Afterthought: Your dissatifaction with your power output can also be very much related to the lack of portwork on those heads....this is something that all the carburetor flow capability in the world cannot overcome.

[beached 1]

Thanks again LO. BTW if I sound like an idiot, you're right! :D
I'm learning as I go..
I saw the very nice prt job on your D3VEs in the other thread. My intakes are no where near the size of yours. A little of the shrouding was removed near the valve area is all. My exhaust was cleaned out (for lack of a better description) of the obstructions like the "smog bump" and some of the shrouding also. However, my ports were not rasied, lowered nor opend up any bigger than stock. In fact, all I did was use stock gaskets as a template and matched them up. Even though I removed the "smog bump" I didn't take out the hump all the way flat. In fact, it kinda lookes like yours (with the exception of the cool looking Shark Fin shape in there) in a way. I was pressed for time and therefore couldn't take it to a shop to be done by a pro. So I left them as close to stock as possible to leave room for a pro job later. Nevertheless this thing runs really hard IMO. Currently it cam spin a (recently rebuilt) MPD SS A/B in a flowed JC bowl to 5250/5300 (5400 ona good day once) RPMs. But according to jack @ MPD, he said I should shoot for 5500 with this setup. I think I can reach this buy ditching the dual plane manifold and getting a slightly bigger carb. I hope..
Not looking to impress anyone with this pig of mine (a 73 Spectra20 that carries 54 gallons of gas). Just want it to be right.
:)

[flat broke]

Gman,
I ran a 850 mighty demon on the 496 right before I decided I wanted more out of the motor. The same carb will be doing duty on the new setup as well. I was really impressed with the throttle response the carb gave with minimal setup over the out of the box condition. The carb comes with replaceable boosters, screw in air bleeds, and is just plain better looking than a holley. All of that and they're less expensive than an HP950; I think I paid right around 5 for mine.
Good Luck,
Chris

[beached 1]

I agree Chris. I have been pretty inpressed with my Demon 750. It's a great carb. Not to mention they come with a nice instructional video for idiots like me.
Summit has the Mighty Demon annular for 499. Not a bad price IMO.

[hack job]

just thought i would throw my .02 in there . i have to 750 on top my 501 ford and if i have to do it again i would go with the single plane manifold. with the single larger carb. fords love cfm . oh and here is a pic of my heads
http://plumbersassracing.com/images/engine/port2.gif
http://plumbersassracing.com/images/engine/rocker3.gif;)

[LakesOnly]

Clean lookin' build, hack job. Here's a similar picture of mine:
http://www.***boat.com/image_center/data/500/350Valve_Train_Install-med.jpg
Beached, the stock intake valve size in your D0VE heads is 2.08". In relation to the intake port cross-section of that head and the flow characterstics you want, the head works best with a 2.19" intake. (The seats you saw on my heads are cut for 2.25". They were re-cut to 2.19".) Next time you have your heads off and are going to get port work done, go with the 2.19 intake and port accordingly. If you port only one side of your head (either intake or exhaust), absolutely port the exhaust first; that's where your major restriction is.
Depending on your approach to exhaust porting of the 429/460 BBF (and the application of the engine), complete elimination of the thermactor boss can hurt flow/provide lesser results than shaping the thermactor into a vane with "trenches" on either side of the vane. Technically speaking, completely grinding away the thermactor boss is probably better than leaving it untouched. If you have any thermactor boss material left over for refining into somwhat of a vane, then leave it in place for that future modification.
LO

[beached 1]

Originally posted by LakesOnly
. If you have any thermactor boss material left over for refining into somwhat of a vane, then leave it in place for that future modification.
LO
I believe I left enough material near the valve stem area for just that. My intention was to help it as much as possible without screwing myself out of a future port job by a pro.
Thanks for the info.

[Blown 472]

Originally posted by beached 1
I believe I left enough material near the valve stem area for just that. My intention was to help it as much as possible without screwing myself out of a future port job by a pro.
Thanks for the info.
Ditto on what lakes sez bout the intake valve, I would leave the stock sized exhaust valve in there.

[Hotcrusader76]

Originally posted by Craig
Annular boosters help when you use a big carb on a smaller motor. They increase signal stregth and fuel atomization, enabling a smaller jet size and the ability to run a larger cfm carb on a smaller displacement engine, giving the low-end feel of a 600 cfm carb with the top end flow of an 850.
Craig
This pretty much sums it up. The 850 Demon should work fine for your application, going with an annular will definitely keep it throttle response happy and with keeping a strong mid-range for that BBF.
~Ty

[beached 1]

Thanks for the reply Hotcrusader, would a Demon 850 annular be your first choice for this application? If not, what would you suggest?
Thanks,

[Hotcrusader76]

If it was my boat and motor I would run an HP950 Holley carburetor. It will need some prepp for your engine in order to perform well, IE 50cc secondary pump.
The 850 Demon is a good choice but it will also need some prep/tuning. Probably more so than the HP Holley. Barry Grant customer service sucks, and trying to remedie an issue with them might take days over e-mail. I'm not trying to scare you off the Demon choice, but be forewarned there's been alot of complaints about their use on many of applications.
Either way if you have a tuning/carb issue give me a call. I can assist you on dialing it in whether it's one of mine or BG's. I always extend my help to ***boat members alike. It's my way of drinking for free:D
~Ty

[beached 1]

Hotcrusader,
If I can get a better setup through another ***boat member, then hell yeah! Thanks!
please check your PM's.
:)