Slant won't start!!?!!?!?

You have 3 cylinders that are to low for them to make power at an idle, 1 2 and 6. may be time to tear into it. You can squirt a little oil in those low cylinder and do another comp. test. If they come up in preasure you have ring sealing problem. If they stay the same it is a valve or headgasket blown or both. 1 and 2 may have a gasket blown between the cylinders.