been helping a friend get his 70 AAR cuda running better, 6 pak is long gone and has been running a single 4 on it, he had a Edelbrock carb on it for a while, ran good but was a real bear to start after running it for a while, so switched to a Holley 650 dp he got from a friend, car ran, idled, and started much better after the swap but had a noticable stumble when you took off from a stoplight or anything, so we did the normal squirter swap,,nothing, changed the pump diaphragm,, nothing, even pulled it apart and checked the gasket and cleaned the circuit,,nothing what I did notice was when you give it a little throttle no gas came from the squirter untill you gave it more throttle so i took the squirter out and moved the throttle just a little and gas would come up in the main body but as soon as you released the throttle the level would drop as if it is draining back leaving a air gap between the main body and the squirter, so I put in a new check needle below the squirter and nothing,,all that I can think of is the check needle seat is mis machined or damaged(how I don't know) in the main body, can this be fixed or is it time for a new body? other than that the carb works excellent.