going by the numbers:
h23a1 = 9.8/1 CR
h22a = 10.6/1 CR
h23a1 = 2.3 Liter
h22a = 2.2 liter
h23a1, 160 peak HP @ 6000 rpm
h22a, 197 peak HP @ 6800 rpm
both have similiar TQ.
going on this information, the head design and cams will be changed during the hybrid but the compression will stay the same for the most part.
meaning higher redline, more cam breathing and an overall increase in performance...EXCEPT for the lower compression ratio.
so i dont see how merely adding a h22a head to a weaker motor is going to make more HP...it may make more TQ since it has .1 more liter and that is the main contributing factor for TQ on an NA inline 4.
~boom