http://runescape.salmoneus.net/quest_xp.html
That site should do you some good.
Quests That Give You Strength Exp
The Path of Glouphrie - 30,000 exp
The Haunted Mine - 22,000 exp
The Chosen Commander - 20,000 exp
Dragon Slayer* - 18,650 exp
Waterfall Quest - 13,750 exp
Roving Elves - 10,000 exp
Dealing With Scabaras - level 7,000 exp
Scorpion Catcher - 6,625 exp
TokTz-Ket-Dill - 5,000 exp
Horror from the Deep - 4,000 exp
Troll Romance - 4,000 exp
Hero's Quest - 3,075 exp
Land of the Goblins - 3,000 exp
Fremennik Trails - 2,813 exp
Tai Bwo Wannai Trio - 2,500 exp
In Aid of the Myreque - 2,000 exp
In Search of Myreque - 600 exp
http://runescape.salmoneus.net/quest_xp.html#strength