Sorry but I'm confused after your description. What 4 holes are you talking about?
Did you replace all of the exhaust gaskets when you put on the new DP and CBE? Did you re-torque everything after 100 miles of driving?
There's really no easy way for gas to get into your oil. If you massively flooded your engine and then let it sit for a while, some gas could get through the gaps in the rings and into spaces where only oil should go. But that's one heck of a stretch and only a tiny bit of gas could get in there.
My first guess honestly is that you're smelling oil and not gas and just aren't differentiating them correctly.