Need help with some cylinders not firing

[Gaz64]

Originally Posted by jhv48

If you have both fuel and spark to the cylinders in question, and you are positive that they are wired correctly, but still no ignition, then the intake valves are not opening and letting any fuel/air mixture into the cylinder. Seems like a longshot, but that's all that's left.

I would still bet the firing order on these cylinders is messed up.

You would also get the same condition with no exhaust valve operation.

My bet is on the intake manifold gasket.

Or "riding" valves. Recheck valve clearances.