B series are great motors and reliable but won't make as much horsepower then kseries that's a fact I seen many built b series at 240-260 range, weight makes a huge difference if you make 255hp on a bseries weigh in with you in the car around 1700 that's a 11.0 estimate car... Now kseries are very expensive the swaps can be cheap but to build and the parts prices are up there I seen a stock K20R makes 230hp completely stock other the fuel rail injectors and fpr..hseries are also great motors with minor bolt ons gain hp