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Discussion Starter #1
I know I could go to the auto part store and buy a couple gaskets to compare, but I figure one of you gear heads already has the gaskets and wouldnt mind taking a picture of them for me.

I would like to lay a 1 pc header gasket for a 289 on a 1 pc header gasket for a 4.6

I am interested in how similiar the port locations are on the 2 engines.

I cannot find a tri-y header for my SN65C and am thinking of using a header for the 1965 289 application and changing the flanges to the 4.6 along with a bit of tube modification.

Thanks!
 

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I doubt that they would be anywhere close. The old 289 had a 4" bore. Our mod motors have a 3.55" bore.
 

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Discussion Starter #3
bore diameter is not a concern, the bore centers is what determines the spacing. I did a bit of searching on the web and found the bore centers are 7/16 wider on the 289.

Looks like it maybe a doable project when I get to that point.

thanks for the reply.
 

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The reason the bore centers are wider is because the bore is bigger. How could this possibly work? 7/16th is a lot and by the time to add that to 4 cylinders its 1 3/4". Maybe I misunderstood your question but I thought you were asking how to put a 289 exhaust gasket on a 4.6L. It won't fit its too long.
 

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Discussion Starter #5
The reason the bore centers are wider is because the bore is bigger. How could this possibly work? 7/16th is a lot and by the time to add that to 4 cylinders its 1 3/4". Maybe I misunderstood your question but I thought you were asking how to put a 289 exhaust gasket on a 4.6L. It won't fit its too long.

I said "I cannot find a tri-y header for my SN65C and am thinking of using a header for the 1965 289 application and changing the flanges to the 4.6 along with a bit of tube modification."

That means just what it says, cut off the flanges from a set of 289tri-y headers and adapted the tubing to fit a set of 4.6 header flanges. Each of 3 tubes will need to relocate 7/16" or a combination of and also address the other clearance issues .

Thanks for your reply.
 

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Ahh. Good luck with your mod. Let us know how it turns out.
 
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