My ‘71 won’t idle with air cleaner on.

[Bad4wd]

Took my ‘71 for its first drive around the block in 20 years. Broke in the engine on the stand without air cleaner. Everything is new on the engine except the rebuilt Quadra jet. Truck runs and idles perfect without the summit brand air cleaner base (14” base open element). Soon as I lower the base on top of the carb (no air cleaner or top) the the engine rpms start to lower and soon die in any gear, slower in park & N. What’s your thoughts.