Removing 340 heads
Two more tips; 1) if you drain the block,both sides, you don't get near the amount of coolant into the cylinders. and 2)usually the heads don't just lift off,but are stuck down pretty hard. I leave two long bolts installed about 4 turns down. I use an iron bar in the coolant ports and pry the head loose, and off the dowels. Then I let it drop back onto the dowels, and remove the two long bolts. Then heave! them outta there.
Instead of prying in the coolant ports, you can pry underneath, going across the chinawall. Or whatever works for you.