I think there are 3 different stock coolers, and numerous variations of each being provided by different oems.
I'm guessing the 4000+ one is the standard A64 one not the heatpipe one.
The fan is 70mm, and at full speed they are fairly powerfull, so i'm guessing around 30 cfm.
I would go and have a look as i have a spare one but the fan is in a pc somewhere. It was a delta, but not a high cfm one just a basic oem one.