I have a typical WOT overheating problem for a couple of years. I have done the the usual W/P, thermostat, bypass, etc. replacement and have finally blown the head gasket on the bottom cylinder. I removed the head with no problems but the exaust manifold has the usual frozen bolts. I am using my usual plan of attack, heat outside bolts ant cut the heads of the center bolts so I can heat after the head is removed. My problem is accessing the bottom row of bolts due to the bottom cowling. Any ideas? Any water passages I might not see that need to be cleaned ? And finally, the bolts are obsolete, does any know size and where to buy ? Any help or thoughts would be helpful.