The tech tips on their website cover all types of information that you might be seeking; for example, they cover all of the different styles of pistons, explain the differences between each grade of piston they offer, and even offer general guidelines on how much nitrous and boost their pistons are capable of handling.
Probe’s Factory Performance Series of pistons are forged of VMS-75 High Silicon Aluminum and have a lightweight design, typically 70 grams lighter per piece that some of the competing pistons on the market. Each piston is CNC-diamond machined at the skirt and ring groove area, which helps to increase power, and they carry a tight piston-to-wall clearance design to help ring seal. They are designed for street and many racing applications and offer a number of other features that make them attractive.
The Sportsman Race Series pistons are designed for more abusive applications and are forged of 2618-T61 aluminum, which makes a stronger design than the FPS line. They have a lightweight forging that helps to reduce rotating weight for quicker spin-up, and have CNC machined domes and valve reliefs for your application.
The piston tech tips page offers suggestions for piston-to-wall clearance for different applications and piston designs along with suggestions for ring gap clearances.
Clearances for crankshaft main and rod bearings are a critical engine dimension that can have a major effect on engine power. Probe has guidelines listed, but also recommends that you consult with your engine builder to determine what is best for your particular application. Of course, they can also build you an engine through their Coast High Performance sister company.
Engine balancing is probably the single most important item to your engine’s longevity – get it right, and you’ve got a bullet that will last through hundreds of runs and thousands of street miles. Get it wrong, and your engine might shake itself apart before you ever get it on the trailer.
A rotating object (like a crank/piston/rod assembly) creates centripetal force, which is the load generated perpendicular to the direction of rotation. The object of engine balancing is to equal out the centripetal forces in both directions, which creates a smooth-running engine.