440 exhaust manifold bolts

I had to pull the exhaust manifold studs out of my 440 to get the exhaust on so I will be using 3/8" bolts. I thought I read somewhere that the threaded holes go into the water jackets and you can have leaking problems. Is this correct, if so what would you recommend I use as sealant on the threads? Also do the intake manifold bolts have oil leaking problems like the small blocks?