[Jeff Higgins]

While the rods and pistons are changed after every run, your typical rod or piston is actually good for 8-12 runs. They pull them and mark them, then put them in their "inspection" group to be x-rayed and magna fluxed back at the shop. The ones that pass are put back in the rotation. Every team has a maximum number of runs they will allow on any given component even if it continues to pass inspection. Interestingly, main bearings last a whole race day and cranks several race weekends.

The new forged blocks are actually strong enough to contain a rod or crankshaft failure. A rod can beat up a cylinder liner a bit, but they simply put a new one in and contnue to run the block. I remember the old Donovan 392 based, and the Keith Black 426 based cast aluminum blocks being all welded up after a season of multiple rod or crank failures punching holes through them. They got pretty ugly by the end of the season.

The amount of stress these things run under is indicated, or manifested, in some very unnexpected ways. Head bolt torque is one of them. Changing the sequence, or torque value, can have a +/- 500 hp impact on power output. Just by torquing the headbolts differently. The block and heads squirm around that much. You would think they would always torque for the maximum power output, but it has an effect on longevity as well. They are just now starting to really understand these things, and the gains they have made just in the last few years as a result have been amazing.