Does not the 4.6L share the same skirt transverse width as the 5.4L? If so, I think that might be the limiting factor in stroking the engine. But if the 4.6L has a narrow skirt, you cannot stroke it to that desired 330ci displacement. Of course, boring also has its limits. Depending on the cylinder spacing, which I think is uniform on all modular engines, you can only overbore so much before you cause fissures to crack open in the cylinder walls.

I do not know the exact dims of the 4.6L block, but knowing the crank volume space and other block dimensions, you can calculate just how much stroke is too much.