May try to call Kent. Talked to him at the Indy show last March. Turns out he and I have worked at the same electric power plant (12 miles from my house) on some of the same outages. I bought a couple of things from him. Super nice guy.
He is VERY cool. And sharp. He held the national record back in 93 or 94 IIRC in a Daytona. I forget the class, but I'm pretty sure it was with W7 heads.
From our phone calls he was the lead on developing the 7 head. It basically started with the 5 casting and then developed from there.
IIRC his record was 7.77 at 167 and I *THINK* that was in C Econo Altered trim.