Lot of blowby after rebuild

[cubillos389]

Hello all, I'm rather new to this forum.

I've been having issues with a lot of white smoke coming from my oil fill cap. The truck is a 2008 Peterbilt 389 with a 550 ISX CM871. When I bought the truck about 8 months ago, it had been rebuilt at a million miles and currently has about 120k on the rebuild. The DPF was clogged when I bought it, I had it mandate'd and the ECM tuned. Since then I've put a turbo on it since before the EGR cleanup it had been leaking oil from the compressor side, so I just replaced it. I get good fuel mileage for what it is, average is 6.8-7.0 with no lack in power. I put a hole in the crankcase breather to relieve some of the crankcase pressure, but I still get a lot of blowby out of the oil fill. I change my oil at 13k, filters every two changes, and I only use up maybe a half gallon of oil every change. I'm not burning any coolant and I don't get any issues with overheating or lack of power.

Any ideas?
Thanks