idle dies

ok, I have been playing today...73 dart 318 with 340 cam and 302 heads.
I did also but a lighter spring in the distributor on one side... when in park or neutral ok. but in gear, and it takes a moment or idle to lower down before goes into gear, too high of idle won't go into gear until around 1000 rpms or so. fixed all the vacuum leaks, new parts, brand new carb form summit, 4100 series. removed brake booster form the equation. idle mixture about right timing around 16-20 to stay running, reset to 12 right now at idle, and distributor vac. .line removed. and carb plugged. floats adjusted to specs, getting plenty of fuel, now the a904 l/up for 1978 is in the car, has a supposedly mild shift kit, done before I got it, I added 5:1 kick down lever, and adjusted the band accruing to information on internet. , once it goes into gear does ok, and shifts ... car on jack stands..... using e-brake and in drive, tried to idle then ends up dyeing out, possible timing still? or maybe am I looking a failing torque converter?, I got it used..... but supposes to work... or is it my distributor spring too light? I'm about frustrated right now with is, runs awesome, sounds great but i can't get it to idle in gear below 1000 rpms....? any thoughts I may over looked?