Ok guys, this one has me looking for some answers and ideas. To start off, I'll just say the motor is a carbed 350, dart heads, edelbrock intake manifold and new edelbrock 1906 carb. Nothing real crazy, just something thats fun to drive and it gets used for work around the property as well. We rebuilt it after the 400 that I built for the truck went kaput... I went fairly cheap on the rebuild. The cylinders were fine, so I decided to pass on machine work and just hit them with a berry bar as I wasn't about to bury a bunch of extra money into another motor. I was looking to just get the truck driving again. I've been having an INSANE amount of oil fouling on the plugs. Mainly the 1,2,3,4 plugs with 3 and 4 being fricken horrendous... we are talking have to take the plugs out and clean/replace them every hundred miles or so because the cylinder won't fire. I think most of this is because the SUMMIT tall valve covers have a poorly designed baffle in them and with a high volume oil pump in the motor they are actually allowing oil to be sprayed up on the pcv valve and be sucked back into the fuel system. when I pull the pcv valve, it is functioning properly, but the bottom of it is covered in oil, as is the bottom of the breather filter on the passengers side of the motor. So, today I decide to go out and do a simple test to see if maybe I have an issue with some piston rings or something allowing a lot of blow by thinking maybe there's something really wrong which is causing a high volume of air through the pcv valve carrying oil out... I went out, pulled the breather filter from the passengers side valve cover, plugged it with a rag, and then pulled the pcv valve out of the drivers side cover. I then held a paper towel over the grommet for the pcv valve and low and behold there is vacuum... and I mean a fair amount of vacuum... immediately my mind goes to a bad intake manifold gasket, or a broken intake manifold all together... I'm going to go out and double check all the intake manifold bolts to ensure they are all tight before I get to tearing things apart. My question is, other than a leaking intake manifold gasket, what else could I look for that would cause vacuum in the crank case? I've done some looking on my pcv valve issue. Moroso makes a grommet that is enclosed with a slit in the bottm. I'm going to order one of them and give it a try. If that doesn't seem to fix things, I may have to resort to building or buying an oil catch can. I guess we will see. I read that there was at one time some motors using a bit of a riser for the pcv valve to get it up and away from the rockers so as to eliminate the chances of pulling oil through the PCV Valve. Anyone ever seen anything like this?