I would say that software guess is fairly accurate. Mine posted 481 ft/lbs torque at 5200 rpms. I am running the rollers and Im sure they help but dont know how much. Nevertheless, you shouldnt have a problem getting the horses and torque you are looking for with this combination.

I still think either cam will work for you. If you are making a daily driver, the 268 would be my pick. But if this is a weekend cruiser, the 284 should be a kick. I checked the CompCams website and the 284 is what they replaced mine with. And it rocks as long as you have the springs to match the cam.