Your going to have to use a huge dished piston to drop that much compression. 8-1/2:1 is usually the most you can get by with boosted(in most peoples opinion that used forced induction). What intake are you planning to use. Only the Brazilian intake matches the ports enough to use. A Clifford or Offy for the siamese heads have or course the siamese ports and would be a very large mismatch to the head.
