anyone know of a off the shelf option that fits? I Need a straight inlet to clear the m62 supercharger intake for my davies craig water pump.

. small block chevy thermostat housing is very very close but just slightly too big to clear the block bracing around the inlet

 

Not off the shelf, but you could modify (weld) a piece of the correct pipe to a drilled (hole saw) out block off plate.

 

I may have found something that seems LS7's use at 3-in center hold the center hole setup