Full rollers will free up a little power due to reduced friction. In my opinion though, I wouldn't use 1.6's with an Extreme Energy cam like I used for the DynoSim pull. These cams are ground at the maximum lifter rise without the lifter digging into the side of the cam lobe and are already at the max for lifter/lobe pressure in my opinion. Putting more pressure on the lifter/lobe interface would be asking for trouble.