If I read it correctly, the heads are done and short block assembled. All I have to add, from what I have heard 280 cfm out of a stock casting is probably achievable. People don’t realize that B/RB heads were like a step kid in the “let’s improve it” idea. The pinnacle head was the hemi, why sink development dollars into the B/RB heads. Those heads fit the bill for the intended purpose. No reason to make the casting better so it can, what compete with the hemi? So it languished developmentally. My X head almost flows the same, ALMOST. The heads in this combo are far down on my “worry” list. Three things are being put together that shouldn’t be. Old rotating technology and small CI’s and a heavy car. Don’t get me wrong. I run in a class that requires outside the box thinking, but you should know that outside the box is where money goes to die.