Scratch in LS1 Cylinder #4

[LS670TA]

Hey gang, looking at buying an LS1 long block. Block casting is 12559376. The guy who has it said the #4 cylinder has a small scratch in it. I haven't seen it in person; he's in the next state over. He's asking $650 but sounds somewhat desperate to sell it. He said the scratch is very slight but worth mentioning. Is this something that can be honed out? From what I've gathered, the sleeves can't be bored out. Would the sleeve need to be replaced? Is that recommended, considering how the sleeves were cast into the block at the factory? Is there such a thing as slightly oversized pistons? How would you compensate for any honing done?

Thanks for any help, I appreciate it. Just want to be sure I'm making the correct decision.

[adam0321]

hmm i would stay away there is always one out there without a scratch just look hard and be patient

[pajeff02]

Buying a used block is always a bit of a gamble -- if that's the way you go there are a few things to look for:

1) Do the cylinders still have visible crosshatch marks from the original hone?

2) Is the scratch deep enough that you can catch it with a finger nail? Also, does it run up and down or across the bore and how deep is it in the bore?

3) Measuring a block is the best thing to do -- with a bore dial gauge check the wear and taper against factory specs (at least as far down as you can with the pistons still in it).

4) Any damage, broken off bolts, cracks, etc... Look it over good!

5) Only with clean cylinders, and preferably just a touch of lubricant in them, how does it roll over? Any tight spots?

6) If the oil pan is still on the motor -- ask to remove it to see the bottom of the bores, pistons and rods. Is there any metal junk in the bottom of the pan, or stuck in the oil pump pickup?

I am sure there are other things to check for and other members will fill you in. My biggest question is why is the seller unloading it?