running out of fuel

[stitch_man87]

ive had some running issues on my maddogg. It runs great unless i hold wide open for more than 30 seconds or so, then it starts to bog, i twist the throttle a few times to get the fuel pumping and good to go for another 30 seconds or so. Up hills is where its causing the most problems. Stock motor with a slightly larger carb. My best guess is that at WOT i don't have enough vacuum to push the fuel pump, and the tank is below the carb so gravity isn't in my favor. The intake is stock but not an "airbox". Its a cone with splash gaurd and some piping. What should i do?