Do you know what the dome displacement on the piston is? I'm just looking at the SRP catalog and they they have pistons with a claimed 10.5:1 CR in a B16, from a 5.7 cc displacement. That's less displacement than the stock PR3 pistons which have a 6.01 cc displacement and give a 10.2:1 CR. So if those are the pistons you have, the CR will be more around 11.5:1 which is not too bad.