In the process of what should a simple task, i needed t5o change the oil filter housing gasket on my M44, however one of the upper longer bolts securing it to the block, the one closest to the front of the car, is rusted/seized. It space out slightly, but i reckon any more pressure could shear the bolt. Ive tried heat, plugs, soaked for a couple of nights. All i can think of now is giving it some welly, and if the bolt snaps then try to extract it, unless it shears in the block. Any ideas?