VETTE60

hey guys wondering if I can get soem insight. I seem to have a flat spot in my throttle now with that surging hesitation. it is not there until about mid throttle and then goes away when I put my foot into it but i can feel a dead spot where it almost feels choked, then opens up at full throttle. when I begin to let off, I feel that dead spot where it feels choket. it is an 89 TPI 350 that has been stoked to 383. this problem has just began and feels like some sort of fueling . TPS checks good. injectors are newer. does not do this at crusing speed until mid throttle. thanks for any input.