Garlocs need sealant or they will leak unquestionably and Zooomer told me a few years back to use a thin coat of GM assembly adhesive, basically the gray rtv in a white tube you get from the dealer that is referred to as the "3100" intake sealant. I lay a thin bead down then go over it with my finger so its not enough to build up but is enough to create a nice seal. On the Gen 3 housings you can often get away with the GM gaskets but still need sealant in the PCV areas. I have not had any trouble with the Garlocs since he told me to use the sealant and they are required for SS and Gen V IC installs as the gasket is stamped out with more area than the Gen 3 OE gaskets are. How did the gasket between the IC core and the lower intake look? Any pics of that one? Do you still have the surging problem and spark plugs getting dirty from oil? Does every spark plug looks the same? A piston with a chipped top ring land doesnt seal as well and will allow more blowby into the crankcase and make for more oil vapors to get pulled in through the pcv system. Running a breather is definately giving you plenty of flow. It also seems that cammed cars have a little more oil in this area. I would say if your car is running fine now with it re-sealed and different gasket and you arent seeing the brownish color on the plugs from oil burning then you are fine. Pulling a stock blower off of a stock engine will show oil in the same exact area of the gasket as yours and more so if the mileage is getting up there on the engine.

ONE SIDE NOTE TO MAKE SURE OF!!!!!

IF you have taken the blower housing completely apart OR swapped with a different housing such as a ported one the black plastic baffle under the pcv valve and oring MUST be there!