This is GREAT, guys... thank you for all the replies.
Brian, it looks like you and I are out-voted by quite a margin
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so, no groove it is
No, W-motorhead, no function, and no effect inside. Just mimicks the countour of the inside. Yes, I originally created the provision for the center bolt, but later realized that on the small port, it's not critical. Not to mention, as orginally intended, this small port version has the material to raise the tops of the runners to match large pot heads... thereby creating a more "conservative" option for guys with large ports.
The large port manifold WILL use the center bolts.
Anyhow, just got back a few miniutes ago, with my prepared "333" truck heads. Valves seats are VERY nice, with the blend into the bowl done with a cutter, creating a super rounded contour into the bowl.
I'll be calling my dyno guy in the morning, to make an appointment.
Over the next few days, I'll be pretty busy