Years ago I had a 1961 Falcon Ranchero that needed a new water pump. I managed to break one of the bolts off in the block, then managed to break off an easy out in the broken bolt! I had the bright idea to use a torch to heat the block to see if it would expand a bit and release it's hold on the bolt. I managed to ignite whatever fuel vapor was in the block and was blown back about 4 feet by the resultant explosion! Cost me my eyebrows and the hair on my forearms!