Have a vibration...

original 340's were internally balanced. harmonic balancer was neutral. crank was balanced with rods/pistons weight. flex plate was neutral balanced. torque converter was neutral balanced. (or flywheel)

then the 340's went to cast cranks. harmonic balancer had an offset. crank was balanced with rods/pistons weight and harmonic balancer and flexplate/torque converter or flywheel attached. flex plate was neutral balanced. torque converter had offset weights. (or flywheel had holes milled)

360's followed the cast crank model. the harmonic balancer is specific to 360's, it has an offset
your torque converter will have weights if you have the stock (neutral balanced) flexplate. if you use the B&M flexplate with the notch cut out, you use a neutral balanced torque converter. (in other words the flexplate OR the torque converter will have an offset balance NOT BOTH)

if you have a stroker with a forged crank, then your harmonic balancer will be a neutral balanced aftermarket, your flexplate will be neutral balanced and your torque converter will be neutral balanced. (it's now an internally balanced engine with the forged crank)

if this doesnt make sense i'd recommend doing lots of research on the differences between internal / external balanced engines.