We are dedicated to giving you the technical support you need, when you need it! Old Pics I don't see a choke on this carb.
The kick-down cable on the TH350 bypasses the modulator and provide full pressure to the governor, enabling the wide-open throttle shift points.
I would not go smaller ID size.
At wide-open throttle low vacuum , the full hydraulic pressure is provided to the governor and the wide-open throttle shift points are selected.