Hi Everyone,


I have a question. A friends '68 400 is not running on cylinders 5 and 8. They both have spark and compression. They share an intake manifold runner. I have seen other engines with the two cylinders sharing a runner where one cylinder has an issue not allowing the other one to run. That runner has the vacuum port to the brake booster so I though it may have been a vacuum leak at the booster. I blocked off the hose to the booster and still 5&8 do not run. Plugs are not wet, has spark and 165psi compression. Any ideas??


Thanks for any help.

 

im thinkin flat cam lobes? but you have compression eh?

 

Spark, compression, and fuel, but won't fire?

That leaves timing, as in they have their wires swapped maybe?

Or, insufficient breathing due to the flat cam lobe...