[blykins]

Too large for a streetable engine.

Peak flow is awesome at 400+ cfm, but what about average and low lift flow?

The port volume is too large as well. Smallest one that I saw was 260cc.

It would make for an awesome race head, but keeping a street engine happy with that amount of volume and flow would be extremely difficult IMO. To get that much flow moving would require some high velocity, which would only occur at higher rpms. I'm thinking you'd see lots of reversion and poor throttle response down low.