Sounds like an accelerator pump, make sure their is no lash between the pump lever and arm. Then test it to make sure fuel comes out of the squirters the moment you move the throttle, do this with the engine off, and check the float level as stated earlier. With your engine their is no reason that an out of the box carb wouldn't work, your engine is basically stock ie; the cam. If the car has been sitting for a while it just might be varnished a little bit, and need a little cleaning up sometimes the check valves under the squirters get stuck, remove the squirter and spray a little carb cleaner in the hole. Be careful not to blow the check valve out of the hole.