I dont know what all you are having done with the bottom end for 900 BUT I just got back my bbc short block where the machine shop ground the crank, bored the block, put in new pop-up pistons, and assembled the rotating assembly for 1000.
As far as the cam and stuff, I would go with a 262 or 268 duration with around 450 lift. Stock push rods and rockers will all work well.
Keep us informed on your progress, and
thank you for your service!