Here is a flowchart I pulled off of alaniz's website; it is a worked s20de head
A stock VE head flows:
242cfm@.500" lift
171cfm@.500" lift
with this work done on a DE head the stock VE still beats it. I am not surpised, just FYI. A DE will need alot of work to get done in terms of bowl and seat work, to be on par with a stock VE head but it can be a bit better too or on par with a mild VE head.Then you need to put alot of money into it.