Lots of people are doing the CTR pistons in B series motors. this was a VERY well informed thread on Honda-tech.com that i think people should know. these are the CORRECT compression Ratios for using a CTR pistons in different B series engines. note the compression on a LS vtec with a GSR head.

For Reference:
STD=Standard Bore
OS=a .25 OVERBORE
P72=GSR head
PR3=B16 Head

PR3 head/B16 Block

STD = 11.643438609136867
.25 OS = 11.703231023151065

PR3 head/B17 Block

STD = 12.193487116069006
.25 OS = 12.256369577319077

PR3 head/B18C Block

STD = 12.58636786521145
.25 OS = 12.649248792586258

P72 head/B18C Block

STD = 12.924594026551906
.25 OS = 12.989047869209281

PR3 head/B18A/B Block

STD = 12.825536009218106
.25 OS = 12.88971493738735

P72 head/B18A/B Block

STD = 13.170743903246784
.25 OS = 13.236528215133324

All calculated using OEM 3 layer gasket @ .026 and the compression height provided by Omniman


Picture of CTR piston VS P30 JDM B16 Piston