Whitehead surpassed Waikato shearer Emily Welch, who set the previous nine-hours record of 648 (72 an hour), in 2007.
The Grant brothers bred Snowline lambs specifically for the event, and Whitehead hoped "everyone can get behind them - because they're beautiful lambs."
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Although Whitehead's record was a solo effort, she said there was a team behind her every step of the way, which included washing the lambs.
"My team was there two days previous for seven hours washing those 760-odd lambs – so it's an effort on their behalf too."
"The day doesn't happen without all the lead up and all the effort that my whole team put in."
Mackay asked her if she was interested in tackling the nine-hour ewe record, currently held by Te Kuiti shearer Kerri-Jo Te Huia.
"The ewe record? Maybe. I think it's about 400 and something [Te Huia sheared 452]."
"I might look into it but my focus is probably going to be the eight-hour [strongwool lamb shearing record]."
New Zealand-based Canadian shearer Pauline Bolay currently holds the eight-hour strongwool lamb shearing record at 510.
While the record was physically demanding - with a 60kg Whitehead handling and shearing lambs that weighed 34-36kg each – it wasn't all about athleticism she said.
"It's very mental as well, it's not just the physical side. You've got to have a good positive mind for it."