Paul I would agree that the ports are tiny on B21/23 heads HERE.I think that makes the U.S. Market a lemon,not the B21/23 engine.If the B20E was all it was cracked up to be we would be driving 94 945's with B20's (of one form or another).The fact is the OHC engine design is a better one and things change over time ,yes sometimes to conform to "smog" laws,(remember those tiny ports) but in general are changed for the better.I whole heartedly agree that putting a normally aspired OHC engine in would be a waste of time.While I agree that you could build a B20E that would go as fast as the B23FT (top speed)I havn't seen a B20 yet that will accelerate as quickly as the turbo especially at cruising speeds.I would argue (you should see me after a beer or 2!) that the B23 would run cleaner and be more reliable also since it could basically run "stock" against the souped B20.
Bub