Cast or Alum.heads for racing.
In that case NEITHER a w2 nor an e-brock is the best choice.
Go buy some w8 or w9's.
Race engine is WAY too general. What are the expectations... he mentions 10-11 range. Don't take much to get there. If someone asked me to build a a SB to go high 10's in a 3300# A body, W2's wouldn't be my first, second, or possibly third suggestion.