K code (Hi-Po) exhaust manifold gasket

CarlF250

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Apr 8, 2005
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Chicago
K code (Hi-Po) exhaust manifold gasket UPDATE: laser cut gaskets

Hello, does anyone know where I can find a gasket for the high performance exhaust manifolds for my 66? It needs to have the bigger holes for the bigger exhaust ports. I checked NAPAonline. They list one with bigger ports, but I went to the store and the guy said that they don't carry it anymore.

I am running Edelbrock heads with bigger ports also. If I can't find it I guess I'll have to make my own. Thanks!
 
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Per the shop manual, it looks like there is/was no gasket used in this application. However, like you plan on doing, it probably isn't a bad idea to use one, especially if your edelbrock heads are Al or your manifolds aren't perfectly true.

Sorry I can't help you on where to find one, just thought I'd share my finding from the manual.
 
K-heads didn't have larger exhaust ports.
Just better flowing exhaust manifolds with the same size ports.
You are barking up the wrong tree.
If you don't have K-heads, then look for the gasket number recommended by the head manufacturer.
 
I put a new gasket for a 66 289 up to my K manifolds and the width seemed correct (I haven't actually measured anything yet), but the height of the openings on the gasket were about .125"-.250" too small.

I will check the gasket recommended by Edelbrock though. Thanks.
 
I just saw a picture in mustang monthly I thought was interesting, no mention of what gasket they used though, unfortunetly.

mump_0405_19_z+ford_small_block_engine_detailing+installed_manifolds.jpg
 
I just saw a picture in mustang monthly I thought was interesting, no mention of what gasket they used though, unfortunetly.

mump_0405_19_z+ford_small_block_engine_detailing+installed_manifolds.jpg

That is interesting. Thanks for the pic. I checked Edelbrock's site. My heads have a 1.60" exhaust port, but the gasket they list for a 289 is 1.25" x 1.48". That has to be for stock heads. They don't list a gasket specifically for their heads.

I need to take some measurements so I know exactly what size a stock gasket is and what size gasket I need. I already scanned the stock gasket, so now I can modify the drawing in AutoCAD to make the ports bigger and laser cut my own gasket.
 
Didn't use any gaskets on mine. Repop Hipo exhaust manifolds mounted on Dart aluminum heads. No problems.

If the manifolds were originals I would have the mounting surfaces machined flat.

:nice: There you go. Many Ford V8's had no exhaust manifold gaskets. With the heads surface machined flat and the manifold the same way, they weren't needed. I wouldn't use RTV, it'll burn to a mess. I'd either use a copper or aluminum header gasket. I'd also port the manifold to better match the head ports.
 
Thanks for all the help guys. I still have a little bit of old gasket material stuck to the heads from the old headers I had. So I'm not sure if it would seal without a gasket. Actually, I cant' tell if it's old gasket material or a very thin layer of paint. How clean do they need to be?

Also, why do you guys suggest using a copper or aluminum gasket?
 
Okay here are the new gaskets I made today. I laser cut two out of some material that has a fiber core with perforated steel on each side. I cut the other two out of a material that has a perforated steel core with a layer of graphite on each side.

I'm not sure which ones to use. I think the graphite will seal better. We used to make the round "donut" gasket out of this material. The one that goes between the manifold collector and the exhaust pipe.

The perforated steel one is much more rigid. This type of material is commonly used on exhaust manifolds. I'm not sure how well it will seal because usually one side is either solid steel or it has a softer material on the other side. I have seen this type of material used on anything from Briggs and Stratton lawn mower engines to huge Waukesha engines that are used in the oil fields.

What do you guys think?

The top gasket is used. Bottom two are new.
gaskets1.JPG


A new gasket on top of the old one to show the difference in port size and location.
gaskets2.JPG


The old gasket on the hi-po exhaust manifold. Way off!
oldgasket.JPG


The new gasket on the hi-po exhaust manifold. That's more like it.
newgasket.JPG