didn't the F-84 need a large length of runway?
Yes. I can remember as child watching F-84s taking off on hot days on a 10,000 foot runway and using every inch.
There was an old joke about a 'short field takeoff kit' installed on the F-84. It consisted of a bag full of small rocks mounted in front of the nose gear. As the joke goes when the pilot wanted rotate he pulled a string to open the bag, the rocks would fall out in front on the nose wheel, the wheel would run over the rock and the airplane would leap into the air thinking it had run off the end of the runway.
Remember the F-84 did not have an afterburner (reheat).