Yes indeed the 617 turbo engines do have the oil coolers but they are there for a reason, to help with the added stress and heat. To me that's a wash. In fact since the piston lives a tougher life in a turbo engine, I would be even more determined to replace them at overhaul time.

Pete,

The liners are plenty thick enough for overbore to the dimension of all available piston oversizes.

Have a great day,