Chevy 250 & 261,
As stock49 points out in the numerical examples in his post in the triple choke thread,
stock49\'s example , there is not much one can do if the airflow demand is low and the venturi area is large. If you have the throttle wide open, you probably want to accelerate, so you might as well downshift and get the rpm up, or back off on the throttle and just run off of the primaries.
I'm not sure if the carb spacer would help. Some method to richen the mixture might help, but the additional fuel would need to be very precisely added. Sounds like an EFI system. There is a limit to what can be done with a fairly simple carburetor; but at least you are not at the mercy of a computer and a bunch of sensors and controllers. I may be showing a little bias here! A little experimentation is always fun and sometimes can lead to something better.
