can a 4k motor be bored out 60 tho safely.

Yes if the bore is still the original size being 75mm

What? He means over bored 60 thou, or roughly 1.5 mm to 76.5mm.

Some people have used 5K pistons at 81mm... although I wouldn't guarantee it for all blocks.

Most blocks will be fine, any decent engine machining workshop will have a sonic tester to measure bore wall thickness. it is a very simple process that is not hard or expensive. anything above .140" wall thickness after boring is adequate.