Difference between a 340 and 360 Torque converter please?

The 360 is a cast crank, externally balanced engine with weights welded to the factory converter. It should either have one weight tack welded on near the drain plug or two smaller weights on either side of the plug. The 69 340 is an internally balanced steel crank motor that doesn't use balance weights. If you grind the welds off carefully and remove the weights, the 360 converter will work fine on the 340