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how much over bore???

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Old Aug 30, 2005 | 10:44 AM
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Racintweek's Avatar
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Default how much over bore???

i know absolutley nothing about SBC's. my buddy cracked a piston in his LT-1 and it ate up the cyl wall pretty good. how much of an over bore can he do and still be safe??
Old Aug 30, 2005 | 10:55 AM
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Default Re: how much over bore???

what block is it
Old Aug 30, 2005 | 11:02 AM
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Default Re: how much over bore???

lt-1 5.7l
Old Aug 30, 2005 | 11:24 AM
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Default Re: how much over bore???

i posting it on http://www.turbomustangs.com/forums/...?s=&forumid=20
Old Aug 30, 2005 | 02:47 PM
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Default Re: how much over bore???

well i know on the early style blocks you can go .0060 over safe i know this because i have did it may times without over heating problems but the lt1 i am not sure of the casting but i would guess the same. manufacturers usually offer pistons in the maximum overbore

so to make a long story short see what is offered far as replacement pistons and go look at the lt1 fourms
Old Aug 30, 2005 | 10:00 PM
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Default Re: how much over bore???

"0.030 is safe.? 0.060 can be thin. Best bet is take it to a shop and have them sonic check ALL the bores. If the block has a lot of shift 0.030 may be too much. You can do a short fill in the block to to gain some strength. Or a tall fill?"
Old Aug 30, 2005 | 10:39 PM
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Default Re: how much over bore???

1mm should do it 20 over stock about the same deal.
Old Aug 31, 2005 | 05:30 AM
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Default Re: how much over bore???

.020 over is .5mm, .040 is 1mm
Old Aug 31, 2005 | 07:45 AM
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Default Re: how much over bore???

Originally Posted by Racintweek
.020 over is .5mm, .040 is 1mm
damn, thats what i get for working at a french canadian vehicle dealership and using nothing but hte metric system
Old Aug 31, 2005 | 01:03 PM
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Default Re: how much over bore???

.030 is a standard punch out for a SBC/LT1, only ones you really have to watch is the 400's.........

You can punch the SBC .060 if needed, but core shift can bite you in the ***.




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