What do the spark plugs "say"? What's your fuel pressure doing?
My 368" SB racecar (Duster) 850DP is 88 square, no PVs, .130 needles/seats, don't recall which shooters or pump cams off the top of my head. Milled choke horn, "6-pack" scoop. Footbrake car, 6000 stall, 904, 5.38s, 13x31 tire, stages @ 1600-2000 and hammered from there. Don't knw if any of that matches your combo.
Maybe you don't have enough fuel pump?