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i'm going to rebuild an engine for my camaro that's been sitting for 2 years now. the engine that was in it was a zz4 motor. it needs to be bored to get rid of rust in the cylinder walls. a knowledgeable friend of mine said some people are having issues punching out late model blocks .030 over. he was saying it makes the cylinder walls too thin because there isn't as much metal on them as the non roller blocks and the end result being coolant in the oil cause of a cracked cylinder wall. anyone else hear of this or have a roller block .030 over with any issues? i've looked for .010 over pistons but can't seem to find them.
 

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I thought the ZZ4 block was already bored to .030 to 355cid...

If some surface rust n the cylinder walls is the issue, a good hone should clean that up without having to bore the block!
 

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A ZZ4 comes from the factory with a 4.0" bore at 350 cu. in. I wouldn't be concerned at all at boring it .030 over. I've done .040 over with no problems, but if you only have minor surface rust you might get away with something less than .030 if honing isn't enough.
 

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Discussion Starter #4
A ZZ4 comes from the factory with a 4.0" bore at 350 cu. in. I wouldn't be concerned at all at boring it .030 over. I've done .040 over with no problems, but if you only have minor surface rust you might get away with something less than .030 if honing isn't enough.
are there any .010 over pistons that don't have to be custom made? i've looked through summit and jegs but can't seem to find any.
 

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Yes there are manufacturers of .010 over size pistons, such as JE and Wiseco, but I'm sure there are many others. Try your local machine shop for a recommendation......good luck with it, Bill
 

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That block P/N is 10105123 and if it passes a sonic test it can be bored as we have bought quite a few now ones over the years but only a couple had tobe sent back because of thin cylinder.


As far as cylinder wall thickness we have not seen a differance from old blocks to the new ones as we see quite a few of the older ones fail the sonic test.
 

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See if your machinist can just hone the block to .020 over. I did this recently with a 400 I'm building and it worked fine. He honed with coarse stones until he got th bores just like he wanted 'em, then used the torque plate for the last few thousandths. Saved me the cost of boring the block, too.
.010 over pistons are tough to find, there aren't many companies that make 'em.
 

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Discussion Starter #8
well i took the block to a reputable speed shop today and they said they will do a sonic test. the guy who helped me said he had plenty of late model blocks at .030 without any problem. so i will probably go that route. thanks for input guys.
 
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