Quote: Those holes you talk about filling in and closing up. Arn't they for for what I'll call the idle air bypass? The earlier tq's had a slot or channel in the bottom casting. This routed idle air into the intk bypassing the butterflies and the idle circuit. The later model brings that passage up to the top casting to where you have shown.
I normally open up the idle jet (idle feed restriction) to richen up the idle. I reasoned that blocking the idle air bypass would mess up the throttle blade to transfer slot position at idle.
If you have more thoughts/info on this, please share. I'll try to post a picture of the earlier model idle air bypass.
The #2 pencil lead holes were used to lean all three circuits; the idle, main and hi speed circuits for emission purposes. That is why sealing both will help the smogger carbs work on non smogger engines, David.
By the way, these are the worst T.Q. carbs to re-calibrate for non smogger use; top pic below:
