scored pistons, is block ok?

I dismantled a block from a early 90's Astro. When I pulled the pistons, I noticed that the the sides of the piston were slightly scored; not at the skirt but closer to the head. The crank bearings were scored as well. The crank itself seems to be fine, I think it could use a polishing and be okay. There is a very small scratch is 2 of the cylinders; I think they will come out with a decent hone job. I know the engine got hot because the oil was very dark and it smelled burned. My question is whether or not the block itself is okay. I've heard that once it gets too hot the block will change the molecular structure slightly and not be usable. Anybody have any info? I'm going to put new rings and bearings in if I can use the block. If not then it's back to the junkyard. Thanks.

Never heard of the heat thing... The block isnt tempered, so I don't see how it could change from the low temps of an overheating engine. I've seen block with the pistons seized into the cylinders so bad they had to be pressed out rebuilt to nice motors. Maybe I'm wrong.. speak up engine gurus

Take the block to a good machine shop and let them look at it they will tell you if it can be bored. A lot of them have cores around if needed.

From a metallurgical standpoint, the iron block would have had to reach and maintain around 800ºF for 10-15 minutes to even start changing the crystalline structure. That's only 300º from melting the aluminum, and about 300º above the point where the oil would have burned (in flames) out of the case. Uneven heating can cause distortion, but the structure of the iron was probably not changed.

Power honing (fixed hone) with a deck plate should clean it up unless the grooves/wear are more than a couple thousandths deep. If that's the case, you'll be boring then hand-honing the surface and fitting oversized pistons. If there is a question, and since you'll be replacing pistons anyway, boring at about $8 per hole seems to be the route to take. Your machinist should be able to advise you better since we cannot see/measure the bores.

Thanks for all the advice. The block doesn't seem to be bad at all. A simple hone job should clean up the cylinders nicely. After I put new rings and bearings in, I should be good as new. Thanks again!