Valve cover info from Ford shows my 78 F150 302 should be timed at 6 degrees BTC. Forums here say 10 degrees BTC. Which is right?

Also at 6 degrees BTC, I have pistons 3,5,2, and 4 that when I pull the wire off the distributor, I do not hear or feel the engine slow down. These are the two middle pistons on the passenger side and two outer pistons on the driver's side. When I pull the wires off the other plugs, the engine slows down and even dies some time. the overall engine doesn't run smoothly but does run.

Is the 6 Degrees BTC right/wrong or what else could cause the 3,5,2 and 4 pistons to not decrease rpm when the wires are pulled? Plugs, wires, coil, distributor all check out good.

 

No one has answered yet!
I've figured out the problem with the 4 cylinders not reducing the rpm when wires were pulled... cause was improper wiring pattern.

Still looking for an answer as to the timing. Why do some forum members say 10 degrees BTC and the truck valve cover say 6 degrees BTC?

 

You have carbed motor with vacuum advance, this section is efi.

Edit Thats why timing is 6 not 10.

 

Set it to about 8 degrees if you need to pass emissions. 10 is fine. Just make sure you set it with the vacuum advance line disconnected.