What size carburator for a 383 stroker?

[tupac]

hey guys what size carburator would i need for my 383 stroker i dont know all the specs on the motor but i was told it has a lunati cam the lift is .610 roller motor and the heads are 71,72 LT1 heads according to the casting number #3973487 i have a holley 600 but i think is to small for it what ya think? is a street truck but i race it once a week for fun any help would be greatly apreciated thanks

[gen0]

http://www.mortec.com/carbtip1.htm
that's a good start for info
according to that formula

((383x5000)/3456) x .9 = 498.7 or a 500 cfm carb

another formula is
cfm = (cubic inches /2) X (Max RPM/ 1728)

so

(383/2)x(5000/1728)=191.5x2.9=555 or a 550cfm carb

*note* both formulae end up with an initial 555 cfm but the first also takes in account the efficiency of the motor which can be purely speculative depending on the types of parts you have installed (IE high performance or OEM)

[timberdoodle]

I would definitely go bigger than a 500cfm..being ive heard and am currently running a 650cfm on my 400hp 350ci Id go with 700 as a good bet, more air = more power after all so dont rob urself.

[pind]

bigger is not always better. Look at the range where you will normally drive this thing, I highly doubt you will be running max rpm all the time. Get a carb that best fits the application. If you go too big, all you do is pour $$$ down the drain for fuel. If you figure your engine's needs for fuel/air at 6000 rpm, you will be somewhat over-carbed at anything lower than 6000 rpm.

Been there, done that. Save yourself some time, coin and grief, and go with other people's experience.

Remember, always learn from the mistakes of others... you'll never have time to make them all yourself.

[gen0]

speaking of past issues, I had a 78 trans am with a 350 running a holley 650 double pumper back when I was younger. I recall my dad trying to get me to put this 500 edelbrock carb he had on it. I went with the Holley after seeing all the local high school kids having these 600+ carbs on their hot rods.

Well I should've listened to my dad, because ended up shooting out black smoke everytime I took off with more then half throttle thanks to running too rich. Not to mention fouling spark plugs left and right and easily flooding the vehicle on cold mornings.

I never did switch from the Holley, and I tried everything I could think off to solve the fouling/flooding problems. rebuilt the carb, diff size jets, etc.. It wasn't until I got a set of corvette 202 heads, installed a full race cam, and went with a set of hotter spark plugs, did the problem finally resolve.

My suggestion would be if it's a daily driver, go with the 550cfm.
If your only racing it, go with a 650 for that overall max speed
If your street racing on the weekends, and driving normal the rest of the week (Normal being no sustained highway speeds), go with something slightly higher than the 500-550 range. A 600 would probably be just right.
*note* if you go with the higher cfm, and you don't drive sustained higher speeds periodically, then change your plugs to a hotter set to help with the fouling problem.

[pind]

one carb that has worked flawlessly for me in the past, on a variety of 350 to 380 hp small blocks, is the Carter AFB 625 cfm. very tuneable, user friendly. an all around good carb for the bucks.

[tupac]

thanks guys i just put a 800cfm edelbrock and this thing feels like it made a diffrence my motor has around 450 horses and i feel like is working better than it was thanks

[StrokedOne]

I have a 67 p/u with a 383. I run a 750 vaccum seconadry with an upgraded spring on the street and a 650 "true" double pumper at the track that has a little work done to it. I make, let's just say' 500 and 500 at the flywheel. I run a little rich at idle but great wide open. Hey, all holleys love to run wide open.That is what they are meant for...lol
Hope that sheds some light.