CREATE TABLE table_67623 ("Year" FLOAT, "Chassis" TEXT, "Engine ( s ) " TEXT, "Tyres" TEXT, "Points" FLOAT)

Which year has an Engine(s) of yamaha v8?
SELECT "Year" FROM table_67623 WHERE "Engine(s)" = 'yamaha v8'
SELECT "Year" FROM "table_67623" WHERE "Engine(s)" = 'yamaha v8'