These are custom forged pistons for the LSJ engine, made for us by Diamond to our specs. They use the high performance 2618 forging and are 11:1 compression. We have found that all supercharger and turbocharger builds make better power at higher than stock 9.5:1 compression. We have also changed out the standard ring pack for a Total Seal AP steel ring pack of 1.0mm x 1.2mm x 2.8mm rings. These will handle the heat and pressure of a nitrous, supercharger, or turbo engine. By going to this ring pack we have also made room to move the top ring down to handle more power and heat. These also have horizontal gas ports to help the top ring seal better. To finish these off we upgraded the wrist pins to a thicker wall H13 tool steel.
The standard Diamond pistons other dealers sell use an iron top ring that is closer to the top and can't handle high power or heat. They also use a weaker wrist pin that will flex under heavy load and cause the piston to distort, this leads to power loss and eventual failure. The standard Diamond pistons are only recommended for up to 400 hp at the engine. Ours are good for 900hp and if you want to go higher than that we can have a custom piston made for you.