Looking for D4B intake Manifold
I snagged an Edelbrock LD4B (which is what I assume you are looking for) off E-Bay, for $112 to my door, last winter. They are still out there and I've seen some go for up to $250.
Mine will be going on my 318 as soon as I attempt & complete the carb rebuild.
Good luck with your hunt. Be patient.