X0101 EFFECT 33 LIVE 2017-10-06 0001193125-17-286326 485APOS 0000844779 BLACKROCK FUNDS 333-216992 S000001507 BLACKROCK ADVANTAGE SMALL CAP GROWTH FUND C000004047 INSTITUTIONAL S000001507 BLACKROCK ADVANTAGE SMALL CAP GROWTH FUND C000004049 INVESTOR A S000001507 BLACKROCK ADVANTAGE SMALL CAP GROWTH FUND C000004051 INVESTOR C S000001507 BLACKROCK ADVANTAGE SMALL CAP GROWTH FUND C000037627 R Shares