Amitab is the biggest film star in Bollywood history. I would start with his films from the 70's. One of my all time faves however is Qurbani starring Vinod Khanna and Amjad Khan. This film features every over-the-top genre device that makes Bollwood great under the influence of Blaxploitation. The only thing missing, if i remember correctly, is the brothers seperated at birth storyline.

good luck,

native son