Oil all over motor ???

Yesterday we boosted up the RPMs to 6000 on our 360, we took it out for a run and now its got a lot of oil all over the engine and compartment. We have a breather cap on the one valve cover and never had this problem before , could it be that since the engine is working at higher RPMs that it needs to breathe more and if so how do we accomplish this. This engine does not have a Pcv valve on it.

Bob