What chasis did the maserati l6s have?
CREATE TABLE "table1_21977627_1" (
  "no" real,
  "driver" text,
  "entrant" text,
  "constructor" text,
  "chassis" text,
  "engine" text
);
SELECT "chassis" FROM "table1_21977627_1" WHERE "engine"='Maserati L6s';