Just wondering what kind of temperature the intake manifold should be on a 1978 400 Ford engine. I have the 4bbl Performer intake and Edelbrock Thunder Series AVS 650cfm carb. The thermostat is a 195 degree stat and keeps the engine on the lower end of the NORMAL range on the temp gauge. When the engine up to operating temp, I've taken some readings with a lazer thermometer. The intake manifold is 200-230 degrees while most of the other engine components (aluminum valve covers = 140 deg, thermostat housing ~180-195 deg, base of carb ~160 deg, etc.). Is the manifold getting too hot for this application? It's so hot that the split wire loom that I have covering the wires that go to the distributor starts to melt against the valve cover and intake manifold on the passenger side of the engine.
Can anyone verify if you are getting the same temp readings I am?

Thanks!

 

you will have some heat due to the water passages and exaust crossover running through the manifold on the end and middle in order to vaperize the fuel you need heat thats the way their designed

 

^^ This.

There is a crossover passage under the manifold that allows a small amount of exhaust gas to cross under the intake manifold between the heads. This keeps the manifold (and to some extent the carb) hot and allows better vaporization of fuel. It also prevents icing in colder areas of the country in the winter. Most "racing" manifolds eliminate this crossover in an attempt to keep the air charge as cold as possible to make the most power, but street driven vehicles need this heat.

So don't worry, its normal

 

Not all wire looms are created equal either. I get mine thru McMaster Carr, hi-temp braided. Gotta love that place, they sell all kinds of cool, quality stuff and fastest shipping I've ever seen.

 

I was wondering the same question just the other dya when I burned my hand on the manifold. I don't know if it was the right/wrong thing to do, but I just put in the edelbrock heat insulator carb gasket...

 

Most "performance" gasket sets block off the exhaust crossover passage, even when blocked off your intake will still be around 200 degrees +/- which is plenty hot enough as to not cause any driveability issues in cold climates, at worst all it does is increase your warm-up time a bit.

 

ok well thanks for the comforting replies lol. Guess I can drive it the way it is then. thanks!

 

Also aluminum has different heat dissipating properties than steel.
So you really can't go by the surface temp applied to function.
Aluminum will always feel hotter.
Your good. Drive it.

 

On an Edelbrock performer manifold, does the engine coolant circulate through the intake manifold?

Since we're talking about heat related questions here, I had a stainless steel exhaust installed (headpipe off the headers all the way back to the tips is all stainless). My concern is the exhaust temp is turning the front head pipe a brownish / bluish tint almost like the exhaust temp is too hot. The pipe is changing this color back to the first muffler. Is this normal? I've checked the spark plugs and they are a tannish color so I'm thinking the air/fuel mix ratio is OK? How would a guy check if I have the correct jetting in the carb?

 

Yes, but only in the front, there are no coolant passages in the rear of the intake.

 

It should be fine. I had to do this with my stock 2v carb and iron intake manifold. My carb would heat soak so badly that it would boil the fuel out of the carb when I parked it. This made the truck REALLY hard to start...Its not uncommon for stainless to change color with heat. Its usually fingerprints, cutting oil and WD40 burning off from manufacturing and fabricating rather than the steel itself burning. Other than checking the plugs, the only way to confirm your Air/Fuel Ratio (AFR) is with a WideBand o2 Sensor (WBo2) installed in your exhaust. You can pick up a stand-alone WBo2 from any number of vendors for about $200 to $250, less if you find a used one. I have an AEM UEGO o2 Sensor and Gauge that I use to make sure my carbs are working as expected. A vacuum gauge and a WBo2 sensor are invaluable tuning tools because I refuse to learn to read sparkplugs

 

Braindamage, talked to a coworker today and he also confirmed that stainless will change colors when heated. I did check plugs and they are tannish color, not white or black, so the carb should be somewhat OK according to Edelbrock tech guy. Guess I'll have to learn how to use a vacuum guage to set the carb.