Need help with this. Installed 360 crate motor in automatic 1973 Dodge Challenger. Engine starts fine but will not stay running when put into drive. Any ideas?  

Check to make sure you carb floats are set properly and that the needle and seat is set properly and not dripping fuel down the throat of the carb.
Check all vaccum lines and make sure the vac. advance is connected to the carb and that it is working properly.
Try setting the timing, if you cannot keep it running at idle rev. the motor to 3000 rpm and set total timing approx. 35 degrees.
Try and let the motor idle, the timing should be around 10-12 degrees with the vac. advance disconnected.
Connect the vac. advance, set the idle speed, and then set the fuel mixture screws.
If you continue to have problems, check for vac. leaks including around the carb and the intake. This can be checked with a propane bottle feeding propane along all the sealing areas. If the engine increases in speed while checking these, you have found a problem that will need correcting. Good Luck.  

Thank you drmopar, I will try this! How can I eliminate the possibility that the torque converter maybe contributing to this stalling issue?
Thanks again!  

Is this the 380hp crate motor, they are very lopy @ idle and would do better with 4 corner idle and a 2400-2800 stall converter along with 4.10 gears.
If the motor doesn't make much vacuum @ idle it's probably gonna stall in gear and in that case it may be time to drill 2 tiny holes through the primary throttle blades in order to strengthen signal to the idle circuit.
Before drilling anything check the vacuum reading @ idle and in gear and at what rpm the engine has to be at in order to stay running in gear. then get a holley book or go on line and check the tech section on the correct procedure.
If your not running a holley or holley design then you have the wrong carb for the application IMO.  

Thanks!!