Boosted LS or Boosted B20. If you want to run NA, B18C1. The H22 is not going to be cheap or as easy, but you would have much more torque over a B series. If you plan on AutoX then the H is probably not the best choice, but if this is a straight line racer the H has the most torque from your list. If you still have the LS bottom end then an LSVTEC is a good option.
I guess what the question comes down to is what (if any) kind of racing do you want to do?