On my 5.3 with a procharger D1SC,I have my crankcase vented to the atmosphere.I can really smell the fumes sometimes and I was wondering if I change to a synthetic oil will it help?I know the alternative to vent it into the intake but I would rather not.

 

Synthetic oil will not help the smell. You will always have some smell of oil, the smell can be reduced in the cab if the breather hoses are ran farther away from the engine bay.