Well, they can, just not right. Yet another lesson learned, at least it wasn't too expensive. Since I realized the MAF/oil filler issue, I decided I wanted a later model style oil fill, the screw in type. At the last swap meet, picked up a nice pair of Vortec take offs. Turns out the oil fill is at the rear driverside, which places the PCV at the drivers side front, opposite of what (my) TPI setup needs, PCV in back. I think even the passenger side breather is at the back too, which is wrong as well. I wonder if the Corvette setups are similar to the Vortecs then, I know even the Vette TPI motors are somewhat backwards compared to Camaro ones. Thinking I might run a longer line for PCV, but that sure makes it hard to reach the oil fill cap. The one I remove maybe twice a year if the truck is lucky lol.