intake and carb sugistions

I have a 512 stroker motor with a 850 double pumper on it right now and it has all sorts of fueling issues flat spots stumbles ect. Everone in my area says I need to step up to a 1050. I would like your opions.
I have a 3500 stall convertor,roller cam, 2 1/2 primary herb McLandles headers and 3.91 gears.