Its second generation MPD.. made by Jerry Magnussen of Magnacharger fame
First Gen was 1 pce, but mine is cut, and I know why.. Really east to pop in with only 2 cylinder, but mine moves around, because it is not positively fastened together like that.. so Idle or synch can change..
That one pictured has some extra ribbing that the early ones did not.
I have 4 different Weber manifolds for 750s at this time, but there is at least 1 that I have not yet owned..