I believe your motor already puts out 207 hp @ the crank(H26). I may be confused w/ the H27 though. Stock CR is 9.8:1 for (H26)?
If I am right, those are pretty damn decent numbers already, probably 170 or so hp @ the wheels. If you invest in a bigger crank (2.9, 3.0 or 3.2L) and stroke the motor, add +1mm pistons and increase your CR, you'll probably be spending several thousand dollars and see possibly a 50-60 hp improvement. If you are looking for an immediate gain, my suggestion would be to lighten and balance the crank, a keeper, because it is so rare, some headwork (although the H26 head comes perfomance flow benched) maybe a cam 284, 288 or 292, overbore on the cylinders and increase the CR to 10-10.5:1(add pistons) (probably the max you'll be able to run on pump gas(at least here in the US), have your rods shot peened, lightened, balanced and rebushed. You'll probably see at least a reasonable improvement in hp, in the neighborhood of 20-25+hp or so. All this would not be cheap. You're probably looking @ $2500 US or so. Or you could do a stock rebuild, add a mild cam and run a bottle. Up to you. Just putting my .02 cents in.