Hi, that manifold you show is off a gasser. The intake plenum bolts to the top of the that cavity with the flapper valve in it to give heat to the intake charge when the engine is cold.

The one on my UNIMOG is identical except for it being a 6 cyl.

Best of luck on your project!

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250