86irocterror

im planing on having a dart 400s/b built with all forged bottom end with 10:1 compression, full roller motor cam specs not sure what lift and duration yet.....and it will have dart pro 1 aluminum heads with 2.08 intake valves and will be ported and polished........bla bla bla so on and so forth...but im trying to figure out what i want to use as far as carb and intake go, the machine shop that will biuld it for me i didnt ask what they think for a carb yet but i want all of your input on this. the shop says it will be in the range of 675to maybe even 700 hp. cam specs are still in the air for me because it will be mostly on the street and show so i need vacume for my vette brakes to work right, and be somewhat driver friendly. looking to have an electric choke as well. i know im not going to get away with just tuning 1 time and never again with that kind of set up, but something a lil less time to keep running. thanks guys

85T/A

theres an equation something like your cubes multiplied by your max rpm then divided by 3. sumtin if im not mistaken will give you the exact cfm carb your motor will need...... now you can get a big cam with a lil duration it wont sound as lumpy but you can do it for instance i m buying a lunati50139 it has like 280 duration and 502/502 lift thats still street runable give you enough vacuum for your brakes and will allow you to run an AT just need a 3400 stal only problem there



i m building a 355 sbc

yallwatchthis

that exact equasion is :
cid x max engine speed / 3456= carb cfm
this will get you very close, 350 turning 6500 will do fine with a 600, 355/7000=720cfm, 383/7000=775cfm, 400/7000 will need about 800cfm

rolling-robert

pro form carb rules!

five7kid

iTrader: (14)

A 400 SBC putting out 700 HP? NA? Wow, that's no street engine!

Assuming 7000 RPMs, that would require the engine to be putting out 525 lb-ft of torque - not likely from a 400 CID NA engine. Regardless, the HP capability isn't really the issue with regard to carb size, it's CID and RPMs, as already noted.

An 850 CFM carb should fill the bill. The formula noted defines the minimum carb size, and assumes a single-plane intake, so going slightly over that typically produces more power.

7000 RPM redline and power brakes typically don't play well together. You can go with an additional reservoir, an electric vacuum pump, or go with a hydraulic power brake system powered by the power steering pump. Something's going to have to give. Since your stated purpose is street & show, the 7000 RPM redline would seem to be the most reasonable sacrificial lamb.
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No choke.

86irocterror

thanks for the help guys i guess its going to be alot of hassle for me then. the machine shop told me it will rev to at least 7500rpms......lol....so i guess i should be looking at at least a 950 cfm carb. and to think i was doing this car to get good gas mileage....j/k! im just worried about the vacume for the brakes cause i might autocross it here and there. the suspension is all biult for handleing not really strait line. so you recomend a vacume canister and stuff like that for my brakes then?