Ken, the thinking behind the 450 not having a secondary accelerator pump is that the very small venturis have such a high flow velocity that they instantaneously pull fuel as soon as they open with no "hole" to need filling by the pump shot. Did that make sense?
What I am trying to say is in a large carb, the secondary pump shot is used to cover up the hole left by the low velocity when the throttle plates first open up. Little carbs have a very high flow velocity so they can flow more efficiently. That will give you something to think about. I'm through now!
