Engine stalls in gear

Did you fill the converter with transmission fluid before you put it in? Or does the transmission have the correct amount of fluid?
+1 on this. I thought the same thing But I would check all the other things suggested too. Take it all one step at a time & rule things out. Especially the vacuum readings. I had the same problems but mine was solved with a carb rebuild. Also, Checking Trans fluid should be done in neutral and not park depending on which transmission so verify that also.