When you have a portfolio of solidly performing investments, drastic action is rarely if ever a good idea. Rather, incremental moves are the way to go and we have one for you this issue.

We’re selling a huge winner, Sunoco Logistics Partners LP (NYSE: SXL), and replacing it in the Conservative Holdings with what should be another, Oiltanking Partners LP (NYSE: OILT).

I don’t claim to have the investment acumen or anything close to the success story of Warren Buffett. But like the legendary investor, my favorite holding period is forever.

That fact is easy to discern from the MLP Profits Portfolio tables, which still feature seven of the Holdings from our very first issue in May 2009. One of these is the stellar Sunoco Logistics, which has returned 250 percent since our initial recommendation. That includes better than 30 percent thus far in 2012.

Unfortunately, over the past year or so except for brief stretches our view has been that units of the owner and operator of refined crude oil pipelines and terminals have been well overvalued.

And up to now the MLP has been able to live up to the lofty expectations in its unit price, parlaying consistent asset growth into distribution growth.

The 9.9 percent boost in the Aug. 14, 2012, payment from the May 15 disbursement was the most explosive increase in many months. And with Sunoco Logistics’ yield now just 3.8 percent, it appears investors are expecting even more ahead.

That may well prove to be the case.

On the other hand, if those sky-high expectations are disappointed in the least it doesn’t take too much imagination to see Sunoco Logistics’ unit price slide back toward USD40.

My top choice for a conservative replacement is Oiltanking Partners, which I featured in a Sector Spotlight in the October issue.

The owner and operator of terminals, storage and transportation assets for refined petroleum and liquefied petroleum gas in the upper Gulf Coast officially became a Conservative Holding on Nov. 1, when it cut below my original target of USD35. Oiltanking Partners is now a buy under USD36.

I discuss the move in the November Sector Spotlight on oil storage.