Buying a 2009 Prius with 425k miles, still runs and drives well!

Yeah on the one NZ that's not a problem You may want to have your head checked for cracks while it's all you might want to have it machined in the back side of the valves cleaned up You can buy a remanufactured head for a one NZ for about $300 from all of the major rebuilders they are readily available A trip to the machine shop with your head can easily cost 300 bucks sanding it grinding etc so it may be beneficial to just buy a redone head from my AutoZone A1 cardone whoever the remanufacturer store you choose shop around see what you can do It's a very old engine still used today but part should be plentiful and not too overpriced not a hard head to rebuild or anything in the shop I would even venture to say that if you wanted you could do it in the field I wouldn't personally but people will they do in Africa and third world countries in the heartbeat.