# Ring Gap size



## liljohn442 (Sep 9, 2010)

I am currently rebuilding a 400 out of a '69 GTO. I need to know whether or not to bore it out. So what is standard ring gap and bore size for this motor.


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## Mr. P-Body (Jan 20, 2011)

Standard bore is 4.120". Ring gap for "stock" rings should be in the .018-.020" range for the top ring. If "original", the second ring should be about .002-.004" "smaller". If the engine has been overhauled or rebuilt in recent times, the second ring MAY have a little "larger" gap (if the builder is paying attention). 

If your cylinders show more than .003-.005" taper, it should be bored to the next oversize.

Jim


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## liljohn442 (Sep 9, 2010)

Thanks man this will be HUGE help.


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