Make sure you're getting spark to the plugs. A cheap spark tester is invaluable here.
if spark, pull the valve cover and observe/check the pushrods,rockers and valve actions. Are they opeing & cosing?
#1 & #2 share the same intake manifold port, could be a blown gasket , loose intakes, cracked intake. While running a squirt of carb cleaner around the gasket surfaces can pin point this.
Good luck & let us know.
Dave
