I have had five or six benz motors rebuilt and only one had pistons worn too much to reuse. The machinist can measure the ring lands for wear and make a determination if they are within spec or not.

Also probably good idea to check cam chain . Guides for same also are probably due.

The bottom end may well be good to go, but if the head is off I would have the valves ground and checked for wear and replace any springs, valves and guides that are out of service specs.

Tom W

__________________
[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.