[freebeard]

In another test conducted by Olsen Ecologic Lab in Fullerton, California, a stock Cummins 5.9-liter engine was compared to one with only a set of SoA pistons installed. The report showed a 15.5 percent increase in horsepower and a 15.2 percent increase in torque.

That closing in on 'extraordinary claims' territory.

But it reminds me of drilling holes in the piston top. www.onallcylinders.com: Part 2: Power-Packed Piston Tech You Can Use!

Gas Porting
One exception to vertical clearance is when gas ports are used in the piston. Gas ports provide a means to supply combustion pressure directly to the backside of the piston ring. As a result, ring vertical clearance can be reduced, and simultaneously, ring flutter can also be reduced significantly. Ring seal goes up along with horsepower. Unfortunately, gas ports are only suited for use with engine combinations where frequent teardowns are common. This means gas ports don’t see use in street-driven vehicle applications. Carbon tends to plug the gas port holes and ring and cylinder wall wear is much faster than more conventional setups.

Typically gas ports consist of 12 to 16 0.040 to 0.060-inch holes drilled vertically through the piston deck. They intersect with the backside of the compression ring groove. Gas porting is most advantageous when a narrow face, lightweight piston ring (such as the 0.043-inch ring) is used. MAHLE uses a different setup. They make use of lateral gas ports, consisting of 8 to 12 horizontal holes drilled into the top flank of the top ring groove. This allows combustion gases to the backside of the ring groove. MAHLE notes it can add vertical ports on a custom basis, but it primarily provides lateral gas ports (they’re an option on a select few pistons in their PowerPak lineup).