This is a Premier Route (N-S or S-N). To claim an FKT on this route, you must meet a high standard of documentation and verification. See details here: https://fastestknowntime.com/premier-routes.

Admin note: The southern terminus for this FKT is Whitney Portal, even though the JMT ends at the summit of Mt. Whitney.

Exhausted, dehydrated & humbled. I arrived 7 minutes ahead of scheduled shuttle pick-up. -- from the journal of Kent Holder's Chilkoot-in-a-day run, 23 July 1998

The following description is from www.n2backpacking.com:

Will Thomas provided information on a short section of the PCT that is an excellent route worthy of its own FKT. This is a 75 mile segment from in Washington, from Steven's Pass to Snoqualmie Pass. "Next to the Wonderland Trail around Rainier, it is probably the 2nd most popular week-long backpacking excursion in Washington", says Thomas. "These two passes ... are the two main (and closest) passes for driving over the Cascade mountains from the Seattle area.