Only running on 4 cylinders

[The Gap]

Currently I am building an AC Cobra and have fitted a Chevy small block v8. Just function tested the motor and it is only running on back 4 cylinders only. I have double checked and confirmed that the HT leads are all ok and distributor is good. Anyone suggest what could be cause of this?

[Rossco]

Hi

Have you double checked that you have all plug leads in the right place?

Are you running efi or carb?

[stevieturbo]

carb and manifold details ?

And as Rossco says, plug wires all in the correct order etc ? And is there any spark on where you think are the dead cylinders ?

How are you determining which cylinders are dead ?

[The Gap]

All plug leads are on correctly, determined that cylinders not firing by touching (very carefully) the outlet manifold. Got Edelbrock “performer” manifold and carb.

[Ian Anderson]

On the Performer manifold, each side of the carb feeds 4 cylinders. Middle tow on one side paired to outside two on other cylinder bank.

Do the dead cylinders match one side? In which case I would think a big air leak or carb bolted to the carb in the incorrect orientation.

Ian

[minorv8]

Try new spark plugs in dead cylinders. I have had a few new ones failing due to cold engine and rich mixture.

[stevieturbo]

On the Performer manifold, each side of the carb feeds 4 cylinders. Middle tow on one side paired to outside two on other cylinder bank.

Do the dead cylinders match one side? In which case I would think a big air leak or carb bolted to the carb in the incorrect orientation.

Ian

Or lack of fuel supply to one half of the carb maybe ?

And you have not confirmed then that there is actually a spark at all 8 cylinders ?

What do the plugs look like ?