I believe you'll develop speed via strength work which includes hill running, either repeats, or running hilly courses as the Kenyans do on a steady basis
Bill RodgersThe most difficult part, when you decide to make running a part of your life style, is the basic initial commitment. Everybody says, 'I don't have the time.' It's up to you to say, 'I do have the time.' For me, beginning to run when I was a student was an ideal situation. However, I've also trained as much as 130 miles per week during periods when I worked a full-time job. It ultimately becomes second nature. It becomes a habit, a routine part of your daily life
Bill Rodgers