Compression Ratio

But, you must remember something else ....
Something I had heard for years, and passed off as something only needed for actual "race" cars, and used to never pay much attention to, but learned the hard way, and again verified on my most recent build, which was a /6 of all things. ..

Most stock engines as built from the factory, actually fall short (some "way" short) of commonly " advertised" compression ratio, largely due to something called "tolerance stack up".
Everything needs to be measured, CC'd, and all the math done to see what you really have ... even on a rebuild for a docile daily driver or else be prepared to be disappointed.