My 280 block had water leaking from the thin water port (between Cyl 2 & 3)into the Nr 2 cylinder. The bores are already bored to 87.5mm. I have now had them honed, as the engine was left standing for a long time, and the water leak had caused some pitting of the bore. The remaining wall thickness now seems very little between the cyl. and the water port. The machine shop say that I may just about get a seal with the head gasket, if I am careful with head tightening etc. Can one weld up the port? and then get the block re skimmed? or can you use any sort of sealing compound to ensure a watertight seal?