340 Block Bored to 4.160????? Help

Piston selection beyond standard overbores (& strokes) and common engines sizes are I st simply expensive but available. There just listed in/with the common sizes normally listed/seen with the common high performance houses.

But there most likely under the custom catogory and price tag. An example would be MP 's create engines with the big bore. AMA 440 small block with the 4.185 size bore.