350 sbc fouled spark plugs
Hi my 350 sbc seems to keep fouling the 2 front spark plugs on the driver's side of the engine. I replaced all plugs about 600 miles ago, and the other day on the highway it starts to pop and backfire out exhuast. Got home and removed al plugs to check, the 2 mentioned were covered in a black tar looking substance, which i managed to clean off with a wire pad, for the time being. The other plugs all ok. The engine has a brand new edelbrock 600 performer carb and edelbrock rpm air gap intake. Other then that engine is bone stock. Being that its only these 2 plugs fouled i dont think its a fuel problem, maybe oil getting into these 2 cylinders? I've heard that it could be worn valve guide or seal, intake gasket, or piston rings (doubtful about rings though as it is only 2 cyl that are bad). Is there anyway i can go about checking before i go ahead and replaced intake gaskets?? Should i pull valve covers first??