Make sure the metering block gasket looks like it’s not leaking around the “tube” that feeds the accelerator pump nozzle.

On your carb it appears to be a cast “standpipe”.
The more common arrangement was to have some of the top of the cavity filled in that area, which provided a broader area of support for the gasket.

You may want to verify that you’re using the “correct” metering block gasket, or at least see if it uses a generic gasket or something a little more specific to that carb.