I am just finishing my project street strip 69 dart and looking for a carb recomendation. It has a 446 with 10.5 Ross piston, h beam rods, Indy EZ heads, Proparts headers and a Comp Cams xs290s cam 252/260 exhaust duration a 10 inch Turbo Action med converter with 3.91 gears and MT 295 55 15 tire about 28 inch dia. I was thinking about a Mighty Demon 850 with annular boosters and mechanical secondaries. How does that carb sound? Just doing some bracket racing and some street driving not every day maybe once a week, so mileage isn't important. Oh yeah m1 intake

I would not buy or use any 4150 carb. that had annular boosters All the Holley 4150 type carbs I've seen that had annular boosters would get fatter the higher you revved it above 5000 RPM, no known way to control the fuel mixture on them above 5000 RPM at WOT

That would probably work but a 750 would probably work better for street driving. Sounds like a 550 hp type of motor which works out to 750 cfm.

Use a dominator and have it prepped by someone who knows what they are doing. A 750 is WAY too small for your CID and gear.

A 750 is plenty big for a 446 pump gas engine with a 252 cam. That engine will run out of air somewhere around 6000 rpm and it will be using about 750 cfm at that point. No reason to put a bigger carb on there and make it lazy down low.

It sounds like this is more of a street car.. a
smaller carb will produce less power BUT drive
nicer on the street... be true to your self and
say how much you plan on racing it.. guys love to
get on here and say street/strip and might run it
once a year on the track... so do you want the power
or do you want better drive-ability

I've got a similar 452 cid 440 with a Holley 9380 850. Excellent throttle response and no over rich on the dyno or at the track.

Everyone has an opinion and they all seem to be different, so here's mine. Bracket racing and street driving would indicate the need for a carb that is dependable, repeatable, with good driveability rather than one that would sacrifice those features in exchange for a few more ponies.

So I think that the tune in the carb will be more important to you than the size. Since you are asking for size recommendations, I would guess that you are not an experienced tuner. Find a good tuner and go with his advice as to size, then have him dial it in.

If someone wants to just pull a carb out of the box and go, there is so much more to that choice than size. Just look at the number of models available in any given size. But no matter what size or brand of carb you decide to buy, there will be plenty of room for improvement in the tune. Most will be close at wide open, but at idle, low engine speed transitions and cruise any carb will be able to be improved.

I`d get a Quickfuel 950 4150 style carb that has all of the best parts like billet blocks, alum. bowls w/sight glasses and removable bleeds that way it can be tailored to your car. I ran an 850 on a stock stroke hi 11-second 360 motor.......these Mopars love air and fuel like no other from what I`ve seen.........

x2, certainly not the Demon 850 annular you mentioned for that application.

My suggestion: Quick Fuel Q-850 (1.39" v x 1.75" throttle). Saw one for sale on Amazon for under $700 just the other day. I don't know how close the OOB tune really is, but Dom (Thumperdart) has gone through one recently, IIRC, and may have more input on that.

Done a couple and they`re a nice tunable piece for sure w/all of the bells n whistles........

FWIW, I didn't see your suggestion before I posted mine shortly after you did yours.

I agree that the combination described by the OP would work OK w/ the 1.45" v "950", but it's also similar to what I used to have when my car ran 11.0s w/ a Holley "950" HP (1.38" v). That smaller venturi, like the Q-850 has, is super responsive on the street, especially w/ limited gear & converter stall.

Either Holley or Quickfuel are good pieces to start with and both can be tuned to perfection.......