Motor stalls when put into gear

I just put the rebuilt six pack carbs on the motor and tuned in at idle, but when I put car in gear it stalls. Timing is set at 18 initial and 36 total around 2600-3000 rpms. It idles around 1100 with 13-15 inches of vacuum. If I put the rear on jack stands and put car in gear with out putting foot on brake it will stay running but rear tire spin kind of fast. Step on break, car stalls. I thought I was told car had stall converter, but guessing not now.
Is it the motor or do in need more stall with the converter?
Author: admin