cfm ?

[Ricky Bobby]

have a 406 thats built pretty decent want to know if a 650 double pumper would be an ok carb for it i have a 7xx edelbrock on it now and its a pos jsut dont want to have to small of a carb and choke it out, has dart intake, world product cast heads, dome pistons, cam is a mystery as this is a mystery motor was built when i bought it with no paper work sounds like has a decent cam in it when its running and does not make very much vaccum as my brakes suck need vaccum can

[jbiscuit]

Maybe this will help

http://www.holley.com/data/TechService/Technical/Selecting%20A%20Carburetor.pdf

[Ricky Bobby]

if i calc my motor out with 85% says i still need at least a 680 spinng close to 7 but in reality wont see past 6500, so if thats correct i would be using every bit of that 650:confused

also lookin around the net lots are saying 750min on these motors? ah well

wheres my taxes so i can buy a new one lol

[jbiscuit]

I would say the 750 would be a good size carb for that motor too. You have a single plane dart intake on that? Put a 750 on it with a carb spacer :) I have about the same cubes as you with the new motor but I have quite a few more CFM in carb sitting on it :)

[Ricky Bobby]

no its a dual plane dart intake, and ur motor is a beast compared to my junkyard shit, also if i put on a spacer stock hood would not close air cleaner is already hittin the liner
http://i9.photobucket.com/albums/a58/LastDemo/PA311661.jpg

[juicedimpss]

if you are running a tight convertor or a low-numerically gear(ie 355 or less) go with the smaller carb for sure. if you are willing to put up with a 3500-4000 stall the 750 may make marginally more power. Usually best to error on the small side for a street car
instant throttle response > a few more HP on the top

[jbiscuit]

^ Good thought process here. I too would rather have the throttle response any day! Makes for a lot more fun

[Ricky Bobby]

have a 3200 stall and shit low gears right now but might have a line on a 3:89 moser axles for 500 with posi unit(complete drum to drum)

i just dont want to have a problem and yes throttle response would be good just dont want to have a issue with it and thats why im asking im hot rod dumb :rolf

[Ricky Bobby]

this site was cool
http://holley.com/applications/CarburetorSelector/CarbSelection.asp

both sites point to at least the 750