I resently bought a 90 integra with a B16 swap in it, I just pulled the motor and reading in this site it does'nt make sence. The serial number on the block is a 5****** digit number, which means that the block came from a 92+ civic SiR2. But the head is stamped with the date 89/6/28. Which means the head came from a SiR1 civic. I think the motor was build from 2 motors. Which would explane the insane dyno chart the person showed me that i bought the car from it showed 164hp at the wheels all 3 times plus or minous a couple hp. Anyone have any commits on this.