318 stalling from idle

That carb may not be for a 318. Certainly not original for a 1970 318. Carter made 505 variants of the AFB, each one essentially custom 'tuned' for the engine it went on.
It is probably a Mopar carb because it has the 3 step metering rods [ raised covers on the met rod pistons ].
Loosen [ not remove ] those covers & swivel to one side; make sure the piston moves up &down freely [ there should be a spring under the piston ].

A 4 digit carb # should be stamped on one of the carb's mounting feet, starting with a 3 or 4. What is it?