SpeedMaster High Rise 4150 EFI Manifold for SmallBlock
I never saw this before but on a google search it looks like someone asked on Facebook about it showing out of stock on Speedmaster's website. I don't have Facebook, but it appears that question had no response.
A place on ebay, from Austrailia, says they have more than ten available, but says they won't ship to USA.
The description implies it's a dual bolt pattern for LA and Magnum, but the one picture looks like LA only.
Interesting.