HP Bi Metal aluminum bearings are best suited for street/strip, all out drag racing, monster truck and medium loaded circle track racing engines . HP’s have great embedability and conformablility characteristics for absorbing debris and conforming to crankshaft deflection. They also work very well with nodular stock type and steel crankshafts. The high silicon content in the aluminum alloy helps keep the ferrite cavities rounded off to prevent excessive bearing wear.
XP pMax Black Tri-Metal bearings are best suited for very high loads for extended periods of time such as circle track, off shore boat, and off road racing. Their load rating is more than 2000 psi higher than the HP bearings and are compatible with all types of steel crankshafts.