Cooler for 4u case + overclocked fx8350

As the title says, I'm looking for a descent cooler for an overcloked fx8350 (4.2-4.4ghz @1.35-1.45v) that is decently quiet and will fit in a 4u rackmount server case (around 145-155mm max height) and also has 24/7 reliability. Would prefer a tower style cooler to better direct airflow front-to-back through the server, but if there is a top-down cooler that does well I'll look into it.

Willing to pay up to $100 for this, thanks.

ever though about a close loop liquid cooler?