Name the chassis of 147 points and engine of ford cosworth dfx
CREATE TABLE "indycar_career_results" (
  "year" real,
  "team" text,
  "chassis" text,
  "engine" text,
  "rank" text,
  "points" real
);
SELECT "chassis" FROM "indycar_career_results" WHERE "points"=147 AND "engine"='ford cosworth dfx';