850dp big enough?

[Moparmatt72]

Starting to second guess my 850, set up is: 440 .060 over, kb pistons were 10:1 (bought for 906 size combustion chambers) now have ported stealths, ported M1, isky 292 cam with 1.7 roller rockers, steel crank and H beam rods. 727 upgraded internals mild, dana 60 with 4.10s and a locker. Hughes 3000 stall converter. Opinions???? Now I do have a 1050 dom I can use, but I can also upgrade the center main body on the 850 to a 950.

 

[67 coronet]

if you have the 1050 why not try it and see how it does.cant hurt,and you can always downgrade back to a 950.i also think the 850 is too small for what you described as your setup.

 

[Moparmatt72]

Thanks for the info. Ill do that then.

 

[Roadbird]

I'll be standing by for this update. Thanks and good luck.

 

[Moparmatt72]

As soon as I finally get my rear wheels in I can finish my dana then drop the motor in, but the rims have been on back order once everything in ill update, should get my wheels after the 15th of this month.

 

[cam383]

I'm using 950 on my set up.I like what she delivers.But I'm kinda curuios what a 1050 will do for me?

 

[Moparmatt72]

Well if you look at most dynos even with mild bb they responed very well to cfm, mopars just love to breath.

 

[Pugly]

850 is the perfect size according to:

http://www.4secondsflat.com/Carb_CFM_Calculator.html

 

[67 B-body]

I think you'll find yourself wanting more converter....... Then your 440 / combo would probably like the extra CFM obtained by the 1050 4500 dom carb.
Did you have your rotating assy balanced? I hope so to get the most from your cam and induction system...
I am wishing for more CFM on my setup... not too terribly different than yours..
440 + .030", Steel crank, H-Beam rods, forged .140" domed pistons, Victor aluminum heads 2.20 valve int and 75cc heart shaped chambers, Victor Intake, MP 590 camshaft with 1.6 rockers up top, 850 Holley DP carb, Mallory ignition, MSD coil, 2" primary tube headers (TTI), 727 trans W/ 4200 rpm Coan converter, 8.75" rear with 4.10:1 gears. Just a quick look at my setup......
BTW,,, I would also like to go up on the converter too,,,, maybe 4800 rpm..... Just feels like it would use a bit more to launch cleaner!

 

[The Shoe]

I built a similar engine for a customer. Similar cam, Air Gap intake and stock 906 heads. 10.3 comp., and hughes 3000 converter. We are running an 830 annular booster carb and it loves it. Read an article recently interviewing several big time engine builders who said the biggest mistake people make now is shoosing too big a cam and too small a carb. Something to think about.

 

[Cranky]

Read an article recently interviewing several big time engine builders who said the biggest mistake people make now is shoosing too big a cam and too small a carb. Something to think about.

That is nothing new. Seems a lot of folks like the lumpy sound of a big cam because it sounds cool when all they are doing is shooting themselves in the foot. I like a cam that sounds relatively smooth but kicks butt. It's kinda like a car that looks like hell but goes like it too!

 

[Moparmatt72]

I think you'll find yourself wanting more converter....... Then your 440 / combo would probably like the extra CFM obtained by the 1050 4500 dom carb.
Did you have your rotating assy balanced? I hope so to get the most from your cam and induction system...
I am wishing for more CFM on my setup... not too terribly different than yours..
440 + .030", Steel crank, H-Beam rods, forged .140" domed pistons, Victor aluminum heads 2.20 valve int and 75cc heart shaped chambers, Victor Intake, MP 590 camshaft with 1.6 rockers up top, 850 Holley DP carb, Mallory ignition, MSD coil, 2" primary tube headers (TTI), 727 trans W/ 4200 rpm Coan converter, 8.75" rear with 4.10:1 gears. Just a quick look at my setup......
BTW,,, I would also like to go up on the converter too,,,, maybe 4800 rpm..... Just feels like it would use a bit more to launch cleaner!

I did have it all balanced, I too have 2" prim 3.5" collectors hooker super comps, I know they have a bad rap for fitment. Maybe ill look into a little more converter, I just went with this cause 3k is when my cam comes into play. Maybe I should step it up to that same size converter. Its mostly just for a street strip car. Well I can always try both carbs and see how it does.

 

[snakeoil24]

stay with 850 big enough

 

[Budnicks]

It really depends how either of the 850dp, 950dp or the 1050 Dominator are set up, what fuel pump your using & the intended main usage of the car, if a smaller carburetor is "set up correctly", with the proper jets, air bleeds, squirter nozzles, accel. pumps & cams, power valves "if you still have them", jet extensions in the rear bowls-on the rear jets, a bypass style "free flowing" fuel regulator, with a return line back to the tank so you don't have fuel pressure spiking &/or drops, with an adequate sized fuel lines #6 or 3/8" min, #8 or 1/2" {or even #10 or 5/8" is better with the larger carburetors} & the fuel-pump supply can maintain a free flowing 7psi rate through out the rpm range of your engine, they will give you great bottom end & good 60ft times, easy to get up on the converter {usually because they are lean & mean}, with very good drivability... But the larger carburetors will flow allot more air & fuel on top end, potentially giving you more mile-per-hr & ET, especially if you already have ported heads, ported intake, {roller camshaft} or large camshaft &/or 1.6:1-1.7:1 ratio roller rockers with a smaller camshaft & large intake valves & "if they are set up properly & if you are able to tuned them properly, I "HIGHLY SUGGEST" YOU BUY THE BOOK "HOW TO TUNE A HOLLEY CARBURETOR", a very good old school rule of thumb, for any race engine is a "minimum flow rate for carburetion of, 2 CFM per Cubic Inch"... 452ci x 2cfm = 904cfm min. That's my 2 cents anyway... It looks to me like you will need more converter too, with open headers, slicks, with that camshaft/valve train, gears & heavy car, maybe even a spacer, like a 1"-2" 4-port properly sized & insulated fuel from the heat...

 

[Moparmatt72]

Thanks budnick will get that book, like I said its mostly going to be a street car due to only being able to make one blast down the track at WOT due to not having a cage, saving up for my full cage ill need for my overall goal. Ill play with both, I'm planning on running full exhaust a 3.5 header back, drag radials and cal trac bars just for traction. Will go with the 850dp tuned for this reason.

 

[67 coronet]

I built a similar engine for a customer. Similar cam, Air Gap intake and stock 906 heads. 10.3 comp., and hughes 3000 converter. We are running an 830 annular booster carb and it loves it. Read an article recently interviewing several big time engine builders who said the biggest mistake people make now is shoosing too big a cam and too small a carb. Something to think about.

your stock heads vs matts ported heads is a huge choke point diff in these motors.that is why the smaller carb works great for this set up,but more then likely not mats.remember it is all about building power.you can make a smaller carb work great,but you need to try bigger carbs if you are trying to build real power.

 

[67 B-body]

I did have it all balanced, I too have 2" prim 3.5" collectors hooker super comps, I know they have a bad rap for fitment. Maybe ill look into a little more converter, I just went with this cause 3k is when my cam comes into play. Maybe I should step it up to that same size converter. Its mostly just for a street strip car. Well I can always try both carbs and see how it does.

Mine is a street / strip application too...
I also just started using the J-W Bellhousing on mine... Making it's first full power pass, I managed to snap my trans bellhousing in half!!:eusa_think: I'm not sure what caused it, but it will never happen again!!!
I have to say,,, it's a little un-nerving staring at a perfectly good "replacement" 727 with a Matabo cut off wheel in your hand!!!! LOL!
The bellhousing is SOOOOO much more beefy than the stock housing!!!

 

[The Shoe]

your stock heads vs matts ported heads is a huge choke point diff in these motors.that is why the smaller carb works great for this set up,but more then likely not mats.remember it is all about building power.you can make a smaller carb work great,but you need to try bigger carbs if you are trying to build real power.

Very true. Those 1.7 rockers will give him, I believe, .544 lift with that isky cam. Im not saying a 1050 wont work, but it should probably be a 4150 style base and not a dominator with an adaptor. Havent seen too much success with that set up. The engine in my bracket car is somewhat similar to moparmatts. I have a .585 comp, a 11.5 comp and ported 906 heads. I run a BG 1025 cfm 4150 style that works fine. About .10 quicker then an 830 annular carb (not the HP style).

 

[Sweet5ltr]

I run a 750 DP Holley, seems to work very well. Completely converted with a pro form main body, baseplate, etc. Read some flow rate tests online that put it over 800 CFM with the main body replacement. Has fantastic throttle response, and cranks up first turn of the key with the 451. The jet size, booster, and power valve from the previous build are nearly identical to what we needed. Night and Day difference to a stock 750DP. Was set up on a 430RWHP solid cammed, 347ci SBF. Also gets half way decent fuel economy. Could go much bigger, but I am not willing to spend $700-$900 to gain a .10 of a second in the quarter.

 

[shag766]

right now i am running a fairly new 850dp single carb on my fresh hemi build and i am pleasantly surprised. i had it on another engine that was more h.p. than the hemi but dropped a valve so it was a spare and i tried it. i use the car pretty much for street use and it has great manners and feels good. granted i am old school and i remember using carbs that were border line too much and having to screw with them all the time to find the sweet spot. if your at the track a lot with headers open you could probably put more gas through it but its too much for cruising around town or the odd trip.
i would start with the 850 and work my way up if it feels like it will take it. keep an eye on your plugs, they will tell you if it is too much and be happy with the reliability of not playing with it a lot.

.02 cents