The H23 is the stronger block and thus has the most potential to survive boosting, but the lack of VTEC somewhat limits the quick horsepower gains. That means you'll have to put more money into the H23.

H23 is usually cheaper. has about 160 hp vs the more expensive H22 with 190-220 hp (depending on which motor). If you aren't going to go very nuts with this get the H22. If your broke get the H23 or save up some more and be patient. If you want to spend tons of money build/FI an H23.

If you have time on your hands get an H23 block and H22 head and get the best of both worlds. You will need someone with experience to do this right, it may cost a lil more up front although long term gains may be very significant, and reliability may be an issue.

noel