Intake heat with a header

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Dec 26, 2016 | 08:39 AM

jrotten67

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Tuned

Joined: Dec 2016

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From: Ohio

Intake heat with a header

I have bought a 78 F150 with the 300 I6. The PO installed a Hedman header. I do not see a heat plate under the intake. I am experiencing some bog at low speeds. I am in Ohio, would a heater plate possibly fix this? Do they sell just the gasket that goes between the factory exhaust and intake? Part number if you know it would be fabulous. If needed I can use this gasket to make a plate to flow water through the intake. Making the plate would be easy. It would just be easier with a template

. Thanks.

Dec 26, 2016 | 08:44 AM

Harte3

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Joined: Dec 2006

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From: Spokane, WA

Check with a parts house about the gasket. I know they come in gasket sets but IDK about just that one...

Dec 27, 2016 | 01:13 AM

jrotten67

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Tuned

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From: Ohio

Here is the part number if anyone else is curious.

9979 Fel-Pro - Intake to Exhaust Gasket

Dec 28, 2016 | 12:58 AM

fordman75

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Joined: Dec 2000

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From: South central, Minnesota

If you are running headers ( that aren't ceramic coated ) I seriously doubt the intake not being warm enough, is a problem! Uncoated headers get HOT! And the header tubes are close enough to the intake manifold it's going to transfer plenty of heat.

To test my opinion, take your truck out for a long drive. When you are done pop the hood and feel the intake manifold. If it's hot to the touch then don't worry about the heat. If it's cold to the touch then go ahead and add the heat plate.

My experience is headers can usually cause a too much heat problem. With this you can end up with heat soak issues. This can cause it to be hard to start unless you are running an electric fuel pump.

I think the heat plates you run coolant through, actually do as much cooling as they do heating. They keep the intake temps more stable. And helps keep the temps from getting too hot.

In a cold weather climate I would be more worried about heating the air going into the carb, then I would be worried about heating the manifold. At least for the winter.

Dec 31, 2016 | 10:39 AM

FuzzFace2

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Joined: Nov 2015

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From: Angier, NC

Quote:

Originally Posted by fordman75

In a cold weather climate I would be more worried about heating the air going into the carb, then I would be worried about heating the manifold. At least for the winter.

That would be my thought also, need to heat the incoming air.

What air filter are you using, open element filter?
Run a stock filter assy. and make a tin to fit around 1 of the header tubes that you can hook a 2" paper hose to and run it from the tin to the air filter.
If the filter assy is hooked up right the flapper door should let warm air into the filter assy. when it is cold and close the flapper when hot.

Over in the 80-86 Bullnose area there is a post on just this issue when cold.
Dave ----

Jan 2, 2017 | 12:52 PM

SixPoppin'

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Joined: Oct 2015

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Headers get very hot...but don't transfer that heat directly to the intake manifold and that is important. Do the heat plate, and if possible use a factory style air cleaner that also scavenges/ducts heat for the incoming air.

I have the hot water plate attached under my Offy DP and it works great until things get down around 20 degrees F. I need to build some kind of system to get the hot air in through the carb. My truck runs lean (confirmed with monitor) at highway speeds in subzero weather because of this problem. The colder the worse the problem.

My truck has the factory A/C and the box is in the way to use a factory cleaner since the DP intake sits so far to the side, darn it. It looks like I need to build a hybrid cleaner but it's cold and I don't want to weld one up so something crude is coming...a cover that allows the air to be sucked up from around the cast headers (efi manifolds).

Jan 2, 2017 | 09:13 PM

Carloespo

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Joined: May 2014

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From: Charlotte

I have a Holley 390 on top of a offy dp. When the weather starts to get cold for the year I typically have to change jets in order for her to run right. If I remember correctly it's 1 jet size down per 20° difference.