It is never too late to invest in mutual funds for retirement. As such, if you plan to invest in some of the best funds, the Zacks Mutual Fund Rank can provide you with valuable guidance.

How can you tell a good mutual fund from a bad one? It's pretty basic: if the fund is diversified, has low fees, and shows strong performance, it's a keeper. Of course, there's a wide range, but using the Zacks Mutual Fund Rank, we've found three mutual funds that would be great additions to any long-term retirement investors' portfolios.

Let's break down some of the mutual funds with the top Zacks Mutual Fund Rank and the lowest fees.

Columbia Dividend Income Fund Class I (GSFTX Quick QuoteGSFTX - Free Report) : 0.65% expense ratio and 0.53% management fee. GSFTX is a Large Cap Value mutual fund, which invests in stocks with a market cap of $10 billion of more, but whose share prices do not reflect their intrinsic value. With annual returns of 10.58% over the last five years, this fund is a winner.

T. Rowe Price Capital Appreciation Fund (PRWCX Quick QuotePRWCX - Free Report) is a stand out amongst its peers. PRWCX is an All Cap Value mutual fund, which invests in small, medium, and large-cap companies, though they end up focusing on bigger firms due to percentage of assets. With five-year annualized performance of 10.59%, expense ratio of 0.71% and management fee of 0.58%, this diversified fund is an attractive buy with a strong history of performance.

VALIC Company I Large Cap Growth Fund (VLCGX Quick QuoteVLCGX - Free Report) . Expense ratio: 0.76%. Management fee: 0.64%. Five year annual return: 13.59%. VLCGX is a Large Cap Growth option; these mutual funds purchase stakes in numerous large U.S. companies that are expected to develop and grow at a faster rate than other large-cap stocks.

These examples highlight the fact that there are some astonishingly good mutual funds out there. If your advisor has you in the good ones, bravo! If not, you may need to have a talk.