Drilling Holes In Carb Throttle Plate Blades

340inabbody said

Guys thank you for all this information. It’s going to take some time to carefully read and understand all this and comment and reply.

I did have the T slots set correctly with the idle screw AND I used the secondary to provide some additional idle speed. But using the secondary is very sensitive. I also installed a wbO2 sensor.

Unless I missed something, I didn’t see any direct reply to my question regarding if tuning the carb by drilling the butterfly’s could improve the idle disparity from in gear and out of gear. Can you guys comment on this please?

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This doesn't exactly fit your situation, but:
I've done it on a high compression cammed MG, manual trans, with a huge weber that wouldn't idle unless you opened the throttle plates too much with the idle speed screw and engaged the main circuit. People do it all the time but it's wrong.

Drilling butterflies worked and is a legitimate fix on a Weber, allowing you to close the throttle blades and engaging the idle circuit, but a better fix would have been to fit a smaller carburetor with less pump shot. And probably 5 other things.

In your situation I'm guessing it'll make the engine idle higher. You could just create an air bleed and see if it helps, like disconnecting an unused vacuum port, and if you like it then consider drilling. It might create other problems that you can't tune away.