If you like stories where operating leverage is a central theme, you'll probably like CLARCOR (NYSE:CLC). This company, which has a strong position in a range of filtration markets like heavy-duty trucks and HVAC, seems to have an uncanny knack for magnifying revenue growth through operating improvements.

In the company's fiscal first quarter, reported revenue grew in excess of 8%, while organic revenue growth (that is, without the benefit of acquisitions) came in around 7%. Operating profits, though, jumped nearly 23%, and the company's operating margin improved by nearly one-and-a-half full percentage points. This growth carried through to the bottom line, where per-share earnings grew 24% from last year's first quarter.

While overall growth was all right (and smack in line with the average estimate), it was a little lumpy amid the segments. The engine business saw top-line growth of 10%, while the industrial/environmental business lagged at 6% growth (2% organic). Interestingly, the company reported that sales into the oil and gas industry were "slow"; that's a little unusual, when you consider that seemingly everybody who sells anything into the oil/gas industry is seeing good demand right now.

The company also reported strong results in the packaging business -- revenue up 22% and operating income up very strongly -- but this is still a rather small component of the whole.

I think it's pretty easy to get a positive feel for this company's future. While many companies that supply the heavy truck market are worried about imminent declines in that business, CLARCOR is an aftermarket supplier, and as long as the trucks keep rolling -- new or old -- they will need filters. Likewise in other markets as well; a lot of its business is recurrent and repeatable.

On top of that, the company has a clean balance sheet, which gives them flexibility to invest in complementary acquisitions and/or more international expansion. Throw in the possibility of ongoing margin improvements and new product launches, and you can make a solid case for ongoing growth.

That said, the stock has had a pretty nice run and no longer looks all that cheap. Others in the filtration business, such as Donaldson (NYSE:DCI) and Pall (NYSE:PLL), also sport robust valuations, but I tend to focus on individual cash flow targets as opposed to relative valuation. So while I like the company just fine, I don't see that ample margin of safety that tempts me to buy today.

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Fool contributor Stephen Simpson has no financial interest in any stocks mentioned (that means he's neither long nor short the shares).