how many miles does it usally take a block to show no signs of hone marks on the cyl. walls

i just got a b20 block and from the way everything looks it has supppper low milage (super clean head, and still see hones in cyl), just trying to get a rough estimate of miles

 

I have rebuild many Honda and Acura engine with over 200,000 on them and still see the factory hone marks. I hope that answers your question.

 

Depends on the piston-to-bore clearances. If the pistons are allowed to wear on the bores, then the honing pattern will wear.

Properly clearanced, cast piston'd blocks retain the cross-hatching pattern for a long time.

I rebuilt my engine at 75k miles and the cross-hatching was very evident. On an improperly clearanced, forged piston'd motor with less than 20k miles on it, the cross-hatching was completely gone all the way around the circumference of the bores.