Carb size help

Im on the Final stages of finishing my motor and have no clue what size cfm to get for my motor, I need a blow thru Carb and Ive found alot of Demon blow thru carbs for a decent price with alot of good feedback, I was looking at ones between 750 and 825 cfm and is to much overkill? or is it better to get a bigger cfm carb for less fuel starvation?
this is my combo
347 stroker
b303 cam
svo 64cc aluminum gt40 heads
scorpian 1.6 roller rockers
edelbrock victor jr intake manifold
paxton novi 2000 supercharger
and all basic bolt ons and msd electronics

Im not sure what size carb will do the trick hopefully someone might know what carb size would fit good or has a similar combo as me
thanks guys
 
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I called there tech support to ask what size they recomended and they said around 600-650cfm does this sound about right?

It sounds right for the size of your engine. The thing that I'm not sure about is the fact you're using a supercharger. Since you're pumping more air into the engine I'm thinking you might need a bigger carb to mix the right amount of fuel with the additional air you're pumping in the engine. But I'm not totally sure about that, so don't take my word as gospel. Someone with supercharger experience needs to chime in and give some advice. But for a naturally aspirated engine, the 600 to 650 carb is perfect; that I do know for sure. Another thing I know for sure is that you can over carburate your engine, which will hurt performance so don't go too big. Bigger is not always better when it comes to carbs. Getting the correct air/fuel ratio is your goal because that will determine how well your engine performs. If you go too big of a carb, you're gonna be running way too rich, which will kill your performance.
 
347 + boost.... and a 600-650 BT carburetor is OK? A little history regarding the "over carbed" stuff...... '65-'66 Shelby 289 ci GT350's came with a 715 CFM Holley...... the 1969 302 Boss had a 780 CFM Holley.... and a 750/825 on a SC 347 setup could be over carbed?...:nono:

A carburetor is a passive device, it depends/reacts to the engine demands IOW..... you can place an 850 DP Holley on a 289 and tune it correctly for street use... BTSTDT moooons ago. For your SC 347 it's better to "err" on the rich side (if you feel a little worried), since forced induction and a lean condition would be a little dangerous for the health of that engine. ;)
 
so how much cfm would you recomend? I was looking into 750cfm but like you said I much rather put a bigger carb on then a to small of one to run lean I just dont want overkill either

Since you're going to get alot of varying opinions on here, maybe you should call a Edelbrock, Holley or any other carb company and ask them what they recommend. Since they make the carbs I'm sure they would know what size carb would be best for your engine setup....But no matter what others say, it is possible to over carb your engine. A carb company will tell you the same thing.