The GT350/GT350R, and the 5.2 Voodoo engine that powers them, are meant to be pushed hard.
Unfortunately some of these engines are known for oil consumption issues and Ford never found the cause. However I suspect that it lies with the oil control rings on the pistons being thin and that, combined with the higher peak crankcase pressures generated by 8200rpm blasts in an engine that has a relatively long stroke, just blows more oil past them into the cylinders. You can borescope the cylinders to confirm that.
There might be some possible solutions.
1. Replace the piston rings, re-hone the cylinders, and repeat the break in. However there's no guarantee that'll work and the original design flaws would still remain. If the engine's still under warranty, you could have it replaced with a brand new unit and hope for the best.
2. Install an air-oil separator on the PCV side of the engine. Although this won't fix the problem, it'll prevent some of the crankcase oil vapors from entering the intake manifold and exacerbating it.
3. Install a vacuum pump to reduce crankcase pressure.
4. Convert to a custom dry sump oiling system. This minimizes the amount of oil that's kept inside the oil pan, reduces windage HP losses, and reduces the risk of piston ring oil blowby.
