Car dies

I cannot figure out why my car keeps dying. I have a 1974 dart with a 318 that has a summit cam and a 600 cfm carb. It idles fine but once it's warmed up and I stop it kinda starts to idle rough then die. I was told that it was my torque converter which makes sense, just replaced the torque converter with a 2200 stall and I thought it fixed the problem but no it's back, what could it be?