Ok I should know this answer but i'm drawing a blank here. I just bought a 89k5 350 for 50 bucks. It's blowing white smoke. I checked the oil and its full of antifreeze how do I tell which side headgasket is bad? I think I will replace both while i'm in there but just want to figure which side is bad or maybe a bad block but cant remember how to check. Also will a blown head gasket cause the engine to have a ruff idle?