Yeah that is about what I'd expect. We did a 505 with a solid roller and 270 heads last year that made a little over 700 hp on the dyno. It is in a Belvedere now and is running high 9's. Another 505 with 270 heads also made right at 700 hp with a street roller cam. It is going into a RoadRunner but the car isn't finished yet. I would expect 700 hp from a 505 with 270 heads if it set up for bracket or even street/strip with a decent solid roller cam.