[jb92563]

Synthetic oils hold up their properties better under higher heat than regular oils, but once they reach their breakdown temp they lose their lubricating properties and the engine is in dire risk of disaster.

Its always good to keep the engine/oil cooler with oil coolers but you are not near the limit for 100% synthetic oils that hold their properties to 400F degrees.
(http://www.synthetic-motor-oil-change-and-filters.com/amsoil_articles/mineral-petrolium-oil-compared-to-synthetic/)

However its the cylinder heads that might reach these temps and if the oil that lubes the piston/cylinders reaches that temp then your asking for trouble.

Since the heads are mostly water cooled I think, the coolant system would need additional cooling capacity as well.

Higher flow water pumps, bigger radiator and additional oil coolers would all help.