In my experience in 3 of 4 cases the pistons can be measured and reused. I have also used used pistons collected from engines which I had on hand which had rods hanging out the side.

They must be measured though to see if they are good. I also have had some which were too worn to use.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.