CREATE TABLE table_35998 ("Code" TEXT, "Vehicle" TEXT, "Year" TEXT, "Displacement" TEXT, "Bore" TEXT, "Stroke" TEXT, "C.R." TEXT, "Max. Power" TEXT)

What code has a C.R of 16.7:1?
SELECT "Code" FROM table_35998 WHERE "C.R." = '16.7:1'
SELECT "Code" FROM "table_35998" WHERE "C.R." = '16.7:1'