Ford 460 glowing manifolds

Hey guys i have a 1989 e-350 motorhome that i just put new heads on. its got new injectors, fuel pumps, filters, plugs wires, cap and rotor. The exhaust manifolds start to glow after i run it in the driveway at around 2500 rpm, takes about 7 minutes. ignition timing is right on (set to the info on the emissions sticker). tried new o2 sensor and temp. sensors. At idle the motor just purrs beautifully. Any help would be appreciated thanks.

How bright do they glow? I’d imagine if you’re revving the thing in your driveway for seven minutes, that engine is going to get really hot and I wouldn’t think it’d be at all unusual for the manifolds to start to glow just a little. Shouldn’t be bright orange or anything, but a little bit is normal for some engines.

Check for a restriction in the exhaust system.


You should get some glowing from the big engines. Also, don’t do that unless a smog check is being done. The vehicle should be in motion at that RPM. It helps to cool those exhaust manifolds and keep everything under the hood from heating up. Headers would start to glow in five seconds.

Under load most exhaust manifolds on big engines glow. Nothing unusual about that…It’s seldom noticed except at night…Just running a big engine at 2500RPM loads it up pretty good…

I’ve seen full throttle dyno runs where the manifolds become almost translucent, bright yellow heat…Engine running normally, no problems…

460 Lincoln motors make a better furnace than a torque producer. Think about how much fuel you are burning to produce all that waste heat…

Your timing is “right” at idle, but where is the spark at 2,500rpm?

And, the problem is…?

When I break in a new motor @ ~2k rpm, I have three huge fans running trying to keep the engine cool. If you have a fan clutch, it may not even be doing anything at those engine rpms so you have way too little cooling for the heat being generated.