Carb size

[Sweet5ltr]

Basing the fact that I am running a 451 with 10:1 CR, .590MP camshaft, Victor 440 intake manifold, and Edelbrock Performer RPM heads. I currently am running a 750 holley :laughing1: with a proform billet main body, metering blocks, and base plate. Would I gain enough power to warrant the change to a 850 holley, or should I just run straight to a 1050 Dominator or 1000CFM+ Barry Grant? Car is DAILY DRIVEN and currently the carb is perfectly dialed in, and cranks up first turn of the key. Made 430RWHP on a 347SBF. Thanks for the advice.

 

[Budnicks]

good rule of thumb is 2cfm per/cubic inch... CFM Formula is; Cubic Inches X max RPM's diveded by 3456 = Total CFM example; 451ci x 6500rpm/3456 = 848.23495cfm but a 1000cfm could work good too, if jetted/tuned correctly, but an 850 Holley should be just about perfect...

 

[67 coronet]

budnicks is correct for a street car that formula is almost perfect.going bigger is drifting into race tune areas,and you start to loose drivability to get max power.

 

[wedge5]

The 850 is going to be more responsive on the street than a 1000+ cfm carb for your set up. In my opinion you should stick with the 750 since you say it runs flawlessly. Be honest with yourself, how many times are you pushing that car like you were on the track.

 

[Sweet5ltr]

I know people have gotten this setup flow tested in the 820-830CFM area, nearly Identical to a 850 Holley. Would the change be necessary ($500 for the carb) for a few cfm? Like I said, the carb is completely set up. Just don't want to be leaving a lot of power on the table.

 

[Tex013]

the proform/quickfuel ratings are like BG's different to holley.you have to check venturi size.when you buy a BG,proform or quickfuel the venturi's are bigger,the 750 is closer to a holley 850.i run a 825 BG which is slightly bigger than a quickfuel 850.i have also used a prosystems holley 1000 based carb.the prosystems carb is only 1-3 hundredths faster but a little higher mph,but slower in the 60' - 330'.
good luck

Tex

 

[RustyRatRod]

You want something that'll make it run like hell? Put one of these on it. They act smaller than they are at part throttle allowing good street manners but will blow your mind when you bend the floorboard.

http://www.summitracing.com/parts/hly-0-80805bk

 

[Meep-Meep]

What is your manifold vacuum at WOT? With a 4 BBL on a street car it should be 1.5 in-hg. Slightly higher won't hurt but very low and you already have too much carb.

 

[383man]

I run a standard 850 Holley DP on my 493. I do want to try a bigger carb but it runs really good on this 850. Street driving is great. Its a stock 850 DP with just the choke valve removed. I have drilled the squirters and jetted it to dail it in but thats all I have done to it and it feeds my 493 ok. I bet the 850 would work fine on your 451 and may go a little faster. Never hurts to try if you have one. Ron

 

[1962savoy]

You want something that'll make it run like hell? Put one of these on it. They act smaller than they are at part throttle allowing good street manners but will blow your mind when you bend the floorboard.

http://www.summitracing.com/parts/hly-0-80805bk

I have to agree I went from a 1050 Dominator to one of these and OMG!!! IT friggin screams now! best choice I ever made!!!!

 

[RustyRatRod]

I have to agree I went from a 1050 Dominator to one of these and OMG!!! IT friggin screams now! best choice I ever made!!!!

Yeah people see "950" and get skeered. It's all about velocity, though.

 

[Budnicks]

You want something that'll make it run like hell? Put one of these on it. They act smaller than they are at part throttle allowing good street manners but will blow your mind when you bend the floorboard.

http://www.summitracing.com/parts/hly-0-80805bk

Great choice Rusty; I'd run it, 950cfm Holley HP, great "fully adjustable" carb, with-out any choke provisions, a bunch of upgrades already done, that are typical of Performance/Race type builds, the $747 maybe a deterent... jet to your specs & go

- - - Updated - - -

good rule of thumb is 2cfm per/cubic inch... CFM Formula is; Cubic Inches X max RPM's diveded by 3456 = Total CFM example; 451ci x 6500rpm/3456 = 848.23495cfm but a 1000cfm could work good too, if jetted/tuned correctly, but an 850 Holley should be just about perfect...

your current 750 Proform could be tuned to work also, it's only "marginally smaller" in actual CFM probably...

 

[Sweet5ltr]

The proform came off of a 430RWHP 347 SBF with a Solid Roller Cam. It is fully tuned/jetted for the car now, and runs great with the .590/312* solid. Had a stock 750 DP on the car initially and the car had no power and really just didn't perform; that was with the .509 hydraulic. I would rather spend $700 on a set of new 2" ceramic headers than on a carb to gain 10-15 more horsepower. Not a strip car, it's honestly a daily driver. Carb has 50cc accelerator pumps, 3.5" PV, etc. already. Drilled throttle blades as well, so it isn't stock by any means. Would cost me quite a bit to get a similar 850 built this way i'm sure, or a new 950 HP.

 

[68 Sport Satellite]

Basing the fact that I am running a 451 with 10:1 CR, .590MP camshaft, Victor 440 intake manifold, and Edelbrock Performer RPM heads. I currently am running a 750 holley :laughing1: with a proform billet main body, metering blocks, and base plate. Would I gain enough power to warrant the change to a 850 holley, or should I just run straight to a 1050 Dominator or 1000CFM+ Barry Grant? Car is DAILY DRIVEN and currently the carb is perfectly dialed in, and cranks up first turn of the key. Made 430RWHP on a 347SBF. Thanks for the advice.

I'm also building a 451 and it will have an Eddy Performer RPM dual plane manifold, 915 heads, and mild Lunati cam. I was originally thinking of running F.A.S.T. EFI right off the bat, but after more research, due to the extra cost of the EFI and not as much ease of dialing in as I was initially thinking, now I'm going to go with a QuickFuel carb first and maybe do the EFI conversion somewhere down the road.

I've been trying to decide between a Quickfuel 780cfm HR series with vacuum secondaries or one of their 850cfm carbs which have mechanical secondaries. From what I'm reading here, especially concerning the larger venturi size of the QuickFuel carbs, I'm thinking the 780cfm should be the ticket.

My car is a '68 Plymouth Satellite, 3.55 gears, will be 727 auto with around 2400 stall, running 91 octane pump gas, mild cam, probably around 9.5:1 compression. I have all along been planning on vacuum secondaries...any reason for a street driven car that I would be better with mechanical secondaries for this setup??

 

[RustyRatRod]

Oh. Then by all means, stick with the phord carburetor. Why on earth would you want to speed it up?

The proform came off of a 430RWHP 347 SBF with a Solid Roller Cam. It is fully tuned/jetted for the car now, and runs great with the .590/312* solid. Had a stock 750 DP on the car initially and the car had no power and really just didn't perform; that was with the .509 hydraulic. I would rather spend $700 on a set of new 2" ceramic headers than on a carb to gain 10-15 more horsepower. Not a strip car, it's honestly a daily driver. Carb has 50cc accelerator pumps, 3.5" PV, etc. already. Drilled throttle blades as well, so it isn't stock by any means. Would cost me quite a bit to get a similar 850 built this way i'm sure, or a new 950 HP.

 

[383man]

Do you have any buddies with any of these larger carbs (by cfm rating) that would let you try it ? That way you could change carbs at the track and see how it works. Ron

 

[snakeoil24]

You want something that'll make it run like hell? Put one of these on it. They act smaller than they are at part throttle allowing good street manners but will blow your mind when you bend the floorboard.

http://www.summitracing.com/parts/hly-0-80805bk

the Holley 950 is one of the best carbs ever made. I almost think it is as good as a Rochester Quadrajet. The 950 is a better strip carb I have used the 950 on afew Hemis in the past, it makes a great signal.

 

[punisher33]

Basing the fact that I am running a 451 with 10:1 CR, .590MP camshaft, Victor 440 intake manifold, and Edelbrock Performer RPM heads. I currently am running a 750 holley :laughing1: with a proform billet main body, metering blocks, and base plate. Would I gain enough power to warrant the change to a 850 holley, or should I just run straight to a 1050 Dominator or 1000CFM+ Barry Grant? Car is DAILY DRIVEN and currently the carb is perfectly dialed in, and cranks up first turn of the key. Made 430RWHP on a 347SBF. Thanks for the advice.

Just buy the 850 double pumper and keep the stock size squirters in it for the street or you can go smaller if needed. When you go to the track you can enlarge the squiters to about 35 or more and pick up some low end. I had a similar set up to yours and it wanted fuel out of the hole more than the stock squirters could give it. It's all about the combination and tuning from there on.

 

[Dennis H]

415 Chassis Dyno. 9.5:1. 850 Demon nice street and strip.

 

[67 B-body]

Just buy the 850 double pumper and keep the stock size squirters in it for the street or you can go smaller if needed. When you go to the track you can enlarge the squiters to about 35 or more and pick up some low end. I had a similar set up to yours and it wanted fuel out of the hole more than the stock squirters could give it. It's all about the combination and tuning from there on.

My 850 needs more squirter too!!!
My build is similar to his as well,,,, a little more here and their, but pretty close..... Mine could use more carb though all around!
I would love to try an 1050cfm 4500 carb with adapter plate.....