also if hindi malaki ang tama ng cylinder walls, pwede naman oversize rings lang ang gamitin. no need to rebore. all the mechanic will do is for you to borrow new rings from the auto supply, install it in the cylinder and measure the gap if it is acceptable. most cylinder walls are not damaged that much unless na overheat na ang engine.

Also having high mileage engine does not always mean that it needs an overhaul, as long as normal lang ang operation ok lang yan. dont fix it if it aint broken.