if it ain't broke add more parts !

give me a couple days, i'm out of towm right now but when i get back i'll dig through some paperwork and find out. one thing i do know is i have 68cc giving me a 9.5:1 comp ratio.
if i went with magnums wich i believe are 58cc, what comp ratio would that give me?
and please excuse me but i'm a little dumb when it comes to 4 strokers [i'm a hardcore into sled and quads- 2 stroke] but when your talking quench i keep thinking squish but i know it's different. i'm pretty sure i know what quench is but rather than me embarrass myself publicly would someone explain.