Figuring compression ratio ....

Formula is ; total space above piston at TDC, plus swept volume, divided by total space above piston.
Rather than trying to do conversions from cc's to inches, and all the calcs yourself, it's easier to use a CR calculator. I like the Wallace racing one.
Bottom line, NO calculator can be accurate without actual measurements of the actual components involved. Some info provided by manufacturers can be believed, some can't. Mopar compression ratios are notorious for being less than claimed.