I've read that people have had problems sucking oil without the valley pan gasket, so some trim the middle valley pan out of a stock gasket and use it with the 1200's. I do know that if you take off the pcv and just run breathers on a street car, especially in cooler or cold weather, you will get lots of condensation in the oil and eventually sludge and rusting in the valve covers (did that for 3 months and always had milky goo on the bottom of the oil fill cap). Plus lots of fuel buildup in the oil so it always stinks of gasoline. On a race car it would be okay, but not a street car.