glowing exhaust manifold

Hi. I'm having some problems with my 81 Vette. My exhaust manifold on the passanger side is glowing red in the middle near the two inside cylinders. The car also seems to be misfiring or detonating. Any thoughts.

Hi. I'm having some problems with my 81 Vette. My exhaust manifold on the passanger side is glowing red in the middle near the two inside cylinders. The car also seems to be misfiring or detonating. Any thoughts.
Obviously the two outside cylinders are not firing. Pull the spark plug, see if its corroded with carbon. I would start with a basic tune up. If that doesn't fix the problem I would see a mechanic. :iceslolan

That or you have a valve problem, or there is a vacume leak causing the two center cylinders to run lean.

The tune up cleared up the problem with the manifold and the misfiring. Thanks. Now it's making this nasty knocking sound. It increases at the same rate as the rpm's. I had the valve covers off three weeks ago and nothing looked loose but I really just barely know what I'm looking at.

The tune up cleared up the problem with the manifold and the misfiring. Thanks. Now it's making this nasty knocking sound. It increases at the same rate as the rpm's. I had the valve covers off three weeks ago and nothing looked loose but I really just barely know what I'm looking at.
The tune up cleared up the problem with the manifold and the misfiring. Thanks. Now it's making this nasty knocking sound. It increases at the same rate as the rpm's. I had the valve covers off three weeks ago and nothing looked loose but I really just barely know what I'm looking at.

you may have spun a bearing. This is going to need a person who knows what they are doing. You may have to drop the oil pan and take a look at your rod bearings. See if they are worn out, or if they have visible damage.

you may have carbon on the pistons
In the old days we would dump a few ozs of water down the carb while we reved the engine
also used rice but to much will clog the exhast

Lean may not be the problem if the fuel is burning in the exhaust

could be a valve but not likely if it runs good
a valve will burn up if it stays open and won;t run after a few hours

that sounds like unburnt fuel

injectors dumping to much

what do the plugs look like when you take them out

that is your best diags

you may have carbon on the pistons
In the old days we would dump a few ozs of water down the carb while we reved the engine
also used rice but to much will clog the exhast

Lean may not be the problem if the fuel is burning in the exhaust

could be a valve but not likely if it runs good
a valve will burn up if it stays open and won;t run after a few hours

that sounds like unburnt fuel

injectors dumping to much

what do the plugs look like when you take them out

that is your best diags