1970 Six Pack Idle Problem

Hope this is in the right spot. I have an original 70 six pack car that used to run like a dream. I had to change the accelerator pump gasket and then the fuel lines due to a stripped nut. After that the car won't kick down from the high idle. I recently changed the choke thermostat and when first started from cold it kicked down when I whacked the throttle. I thought it was fixed. Then I restarted it after about half an hour and the idle wouldn't come down even after I tried whacking the throttle. What am I doing wrong ? What else should I try ?