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I talked to a guy that said that it is a good idea to bore an engine .030 over, even if it doesnt look like it needs it. He says that this ensures there the same bore on all 8. I am going to start to rebuild my engine and it has nothing wrong with any ridges, and are all very close to the 4 inch diameter, none bigger than 4.01 (if that). Is there a need to bore it? or just get it honed, or just magnufluxed? thanks
 

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If all of your bores are 4.010", then I would suggest a .020" or .030" overbore. This will make sure you will have 8 cylinders that are perfectly round, no taper, and the correct piston-bore clearance. Considering that most forged pistons measure 3.998 (standard bore), then your piston-bore clearance would be .012". That's quite a bit. On a street motor, the rings would wear prematurely and it would be a bit noisy when its cold.
 

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I like to have a engine bored the least amount....If 0.020 is enough to straighten up the bore that's good...leaves more for next time...It seems lots of machine shops like to make the first cut at 0.030,,guess thats where most blocks clean up....Russ
 

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The parts are usually cheaper and more readily available in the common sizes such as .030 .Unless you have a rare block like a 427 or something its usually not worth the hassle to bore it a smaller amount such as say .010 even if thats all it needs.
 

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Each bore needs to be mic'd in a few places to see what it has worn to. If it will clean up with just a hone and still be within spec for the type of piston you are running then just have a hone done. Theres no reason to cut material off the cylinder walls for no good reason. Use file fit rings to ensure you get your gaps.
 
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