What was the cylinder size of this engine that was made with only 88 pieces?
CREATE TABLE "engine_num7002" (
  "class" text,
  "firebox" text,
  "cylinder_size" text,
  "valves" text,
  "valve_gear" text,
  "number_built" text,
  "years_built" text
);
SELECT "cylinder_size" FROM "engine_num7002" WHERE "number_built"='88';