My specs are for a 15/1 compression 550 cube motor, so the specs won't compare. 285/296/114 with .867 int and .800ex lift.
On my 499 low deck motor with 13/1 compression and bowl ported 440-1 heads i ran a Ultradyne 283/290/108 with .740? And .680? Two things come to mind to help. That cam needed SPRING! I picked up a bunch by putting a 300+ seat pressure spring in it, and looking back there was more power available if i would have gone to a better pushrod. So if you have good enough valvetrain parts you can run a more agressive cam. That is why i mentioned Jones. You need a plan= lifters,pushrods,rockers, springs, all spec'd to fit the cam design or vise versa.