Disappointed magnum head flow numbers....

OK my build is based on the 360/380 crate, which i have read that regularly dyno at 400 hp, im hoping 530 hp and 500 torque, does that sound reasonable ?
OK my build is based on the 360/380 crate, which i have read that regularly dyno at 400 hp, im hoping 530 hp and 500 torque, does that sound reasonable ?
I doubt it.

My 388" 360 based race motor started life with ported w-2 heads flowing 294 cfm intake, 13-1 compression on alky, 750 Holley DP, dizzy locked at 36 degrees, Crower solid lifter cam 580/580 with a 260 degrees duration @ .050... 575 HP @ 6,000 rpm.

Now I'm shooting for 625 with my 850 carb, more cubes, lighter valves and a better cam. Still might not make it...