First I would get rid of the Summit RACE Damper.
360's are very different in balance than 273,318
and 340's (THEY ARE EXTERNALLY BALANCED)
Stick to the Mopar Performance Damper that is
compatible with the offset balance (external) 360.
Recheck the specs on the B&M flexplate, (weight
INDEXED CORRECTLY!) and 145K torque converter.
Actually, the converter should have never had the
weight removed. It really should have been checked
from the beginning for the proper application (food for thought). Last, I would look at the trans input shaft for excessive play (again food for thought).