running problem

I have a supercharged 351 with a paxton sn200 blower on it. It has a 600 lift cam, vitor intake ported and polished, afr 205 heads, aeromotive fuel system, msd ignition, anderson pms, 3 bar map, 38lb injectors, 75mm tb, 80mm mass air and a lot of other stuff. at idle it runs fine, sometimes when I give it gas to rev the rpms it sputters like it is running out of gas, whenever I rev it up and let off the gas as the rpms are coming down it dies. does anyone have any suggestions about what I should be testing or looking at.
fuel pressure is at 50psi, when reved it goes to 40-42psi.
the aeromotive system does not have the y'block, sumped tank. it has a pick up in the tank, feed and return lines with both fuel rails tied together. only on fuel rail is fed and transfered to other fuel rail.