Does anyone have any idea how long a heater core replacement is rated for on a 97' F-150?

I'd like to do it myself, but it appears the whole dash needs to be removed and I've read that the AC will need attention as well.

Thanks in advance

 

..ok, gordy, it'll be a 6 hour charge to R&R the heater core..that doesn't include evac and recharge of the AC..thats another hunert bucks.

See....I don't need your guys's help anyway!