After everything I've been researching on this, it appears there's no way around new air filter, pipes, and PC on the new motors. These motors are just set up too lean, for EPA Compliance, for any decent performance or modifications as stock. I'm understanding that these 3 things alone will provide a 15-20HP increase (from 75 up to 90-95) & 10ft-lb torque increase (from 90 up to 100). I'm hoping I can live with the stock cams and that the big motor will have some decent pull on the highway while getting reasonable gas mileage. Not looking to build a drag motor just a good, strong, reliable touring motor that pulls nicely up hills or when you need to pass.