CREATE TABLE table_37525 ("Type" CLOB, "Numbers" CLOB, "Year built" FLOAT, "Quantity built" CLOB, "Power  ( horsepower ) " FLOAT, "Max Speed  ( km/h ) " FLOAT)

What is the max speed of the unit with an 8+4 quantity built before 1971?
SELECT SUM("Max Speed (km/h)") FROM table_37525 WHERE "Quantity built" = '8+4' AND "Year built" < '1971'
SELECT SUM("Max Speed (km/h)") FROM "table_37525" WHERE "Quantity built" = '8+4' AND "Year built" < '1971'