Is the stock 1968 340 converter neutral balance. My 408 stroker motor calls for a "weighted 360 pre magnum flex plate" I'm using a b&m 10236 flex plate and a stock 340 converter. I have a small vibration that's bugging me. eliminating suspects

b&m 10236 flex plate
Chrysler '71-'92 externally balanced 360 with A-727 (These special Chrysler Flexplates must be used when changing converters on an externally balanced engine.) Is this considered a weighted flex plate? Thanks