H116CP vs H405CP

Actually, the compression height in the Summit catalog is incorrect for the 405's; the H405CP's CH is actually 1.637". (The 1.576" CH applies to the dished top 405P piston.)

The 405's will drop around .75 point of compression ratio in a typical installation.

I do believe that the 'H' in front of the H405CP PN means hypereutectic.... just like 'L' in front of the PN meant forged in the old TRW PN system. Per Federal-Mogul, the H116CP and H405CP are made from the same FM-425 alloy.

Price difference? I can only speculate demand, lower CR, and the lack of pin ring grooves in the H450CP's....