Exhaust Manifold Temperatures

[Frank D.]

Hi Guys:
1965 327/300 HP auto w/air. Does anyone have a ball-park figure for how hot the exhaust manifolds get in normal driving? My dashboard water temp gauge was reading 135 degrees F after driving for 30 minutes so I shot the engine and radiator with a temperature gun. In the process, I also shot the exhaust manifolds from the top of the engine. Driver's side was 414 degrees F and passenger side was 449 degrees F. Is this normal, and shouldn't they be the same approximate temperature if the car is functioning properly? (it is stumbling heavily at idle)

Thanks in advance,
Frank O'Donnell
Troy, VA

[Wayne W.]

Re: Exhaust Manifold Temperatures

Most I have checked are in the same ballpark, and seldom are exactly the same.

[Stuart F.]

Re: Exhaust Manifold Temperatures

The passenger side will usually be higher due to the heat riser valve - even if open. This has been my experience. Also, your temps for anL-75 are about right, my L-76 usually shows a little higher.

Stu Fox

[Frank D.]

Re: Exhaust Manifold Temperatures

Thanks Wayne and Stuart for the quick response. ONE ADDITIONAL RELATED QUESTION. Is it normal for there to be blackening (burning, crusting) of the orange engine paint on the intake manifold above the middle exhaust manifold ports? I thought maybe unusually high exhaust manifold temperatures were causing this. (I already double-checked to make sure my heat riser valve was not reversed.)

Thank you,
Frank

[Stuart F.]

Re: Exhaust Manifold Temperatures

The exhaust cross over will show signs of heat on the painted intake manifold. The amount and kind may be due to the thickness and paint used on the manifold. Usually, it just looks like the paint was burned away, similar to the exhaust manifolds when new - gray and bare metal. Black and flaking may just be a lot of paint thickness and perhaps not a heat resistant paint.

Stu Fox