Sac

Using the formula CID=Bore Diameter x Bore Diameter x .7854 x stroke x number of cylinders.

The stock bore and stroke is 88mm or 3.4645" and a stroke of 98mm or 3.8583" .020 overbore would be 88.5mm or 3.4845" that overbore would be figure out to 147.1728 cubic inches. Perhaps they did not carry their dimensions to .0001 but that is where the specs are set for this engine. The problem I see is they chose some sort of very accurate CID dimension, when a simple .5mm or .020 over bore will be allowed for wear would be simpler to understand and less open to debate.

Most stock replacement pistons OEM or re manufacture replacement ones are identical including weight and crown dimensions.

That being said I think looking for a late model low mileage motor while costing a premium would still be cheaper in the long run than a overhaul and possible overbore.

Honest Dad himself