Convertor adjustment for new combo

Another anecdote : there was a guy who raced at our 1/8 mi.drag track with a 51 chevy coupe, with a small inch sprint motor that he shifted at 8000+. Lots of people told him his trans or converter was garbage, eight grand from one end to the other, sounded like he left in high gear. He thought the converter was perfect, it stalled at six grand......
He finally changed converter, picked up almost a full second.