The vendor who I thought still had the B-block version in stock shows 0 units now. They do show 2 of the RB version on hand, presuming they keep their web site up to date.

Don't know how the RB version w/ Andy's 4150/4500 shear plate adapter (I think I bought his last one) would compare to my RB Trick Flow 4150. I have experience only w/ modified RB 4150 M1 intakes, which make good torque but don't make the peak HP of something like a Victor 4150 or Trick Flow 4150.

The big advantage of the M1s are their low height compared to the Victor/Trick Flow style intake. Figure as much as an inch lower at the carb mounting pad, IIRC, although the M1s are angled w/ the carb lower at the front of the intake.

EDIT: I looked closely at the "before" and "after" pics of Andy's B-block intake that got Wilson-ized. The more I looked, the more I saw where they'd welded material to allow the runners to be opened up from the plenum to about half way down to the head. A sh!tload of work went into that thing...