New Edelbrock carb

I seen some footage from Sema and they were showing these and I checked on the edelbrock site as well as summit and there was nothing. I'm wanting to buy the 850 AVS 2 for the 408 build. The 650 that I run on the 318 is a pearler . It runs so well with this carb
How built up is your 318? I'm thinking the 650 is more then I need for my 250hp 318. I'd love to hear your engine numbers before I make a decision next Spring. Thanks