VS cam is what, 350.

Now you need a S/c gasket, possibly valve cover gaskets, LIM gasket, might as well replace the lifters since its all apart ($120 for a 16 LS7 lifters if you hunt for 'em), then a front cover gasket set, crank bolt, cam bolt, new timing chain and tensioner or just a timing set.

It adds up.

XP or S1X would give you a better chance of 12's than the VS.

VS + meth or I/C should work.

But no one can really tell you 100% because your engine will respond differently to mods.