Investors with an interest in Manufacturing - General Industrial stocks have likely encountered both Altra Industrial Motion (AIMC) and Dover Corporation (DOV). But which of these two stocks presents investors with the better value opportunity right now? Let's take a closer look.The best way to find great value stocks is to pair a strong Zacks Rank with an impressive grade in the Value category of our Style Scores system. The proven Zacks Rank puts an emphasis on earnings estimates and estimate revisions, while our Style Scores work to identify stocks with specific traits.Right now, both Altra Industrial Motion and Dover Corporation are sporting a Zacks Rank of # 2 (Buy). This means that both companies have witnessed positive earnings estimate revisions, so investors should feel comfortable knowing that both of these stocks have an improving earnings outlook. But this is just one piece of the puzzle for value investors.Value investors also tend to look at a number of traditional, tried-and-true figures to help them find stocks that they believe are undervalued at their current share price levels.Our Value category grades stocks based on a number of key metrics, including the tried-and-true P/E ratio, the P/S ratio, earnings yield, and cash flow per share, as well as a variety of other fundamentals that value investors frequently use.AIMC currently has a forward P/E ratio of 19.90, while DOV has a forward P/E of 21.69. We also note that AIMC has a PEG ratio of 1.33. This popular figure is similar to the widely-used P/E ratio, but the PEG ratio also considers a company's expected EPS growth rate. DOV currently has a PEG ratio of 1.89.Another notable valuation metric for AIMC is its P/B ratio of 2.04. The P/B ratio is used to compare a stock's market value with its book value, which is defined as total assets minus total liabilities. For comparison, DOV has a P/B of 6.16.These are just a few of the metrics contributing to AIMC's Value grade of B and DOV's Value grade of C.Both AIMC and DOV are impressive stocks with solid earnings outlooks, but based on these valuation figures, we feel that AIMC is the superior value option right now.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Altra Industrial Motion Corp. (AIMC): Free Stock Analysis Report Dover Corporation (DOV): Free Stock Analysis Report To read this article on Zacks.com click here.