Intake manifold choices

cany,
I read your initial post again. I doubt an AG intake will fix your problem, nor will a bypass fuel system. You implied that the f/bowls were not hot to the touch, so rules out fuel percolation. Could be pressure build up in the f/line after switching off the engine.
[1] What type of pump do you have now?
[2] Do you know how much HP the engine makes? An estimate if unknown. This needs to be considered if changing f/pumps.