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11/29/2018 6:43 PM  #1


cast iron manifolds on aluminum heads?

Is there any reason not to use the original cast iron exhaust manifolds on a rebuilt 1967 289 that now has edlebrock aluminum heads?  Any precautions to take? Thanks.
 

 

11/29/2018 6:48 PM  #2


Re: cast iron manifolds on aluminum heads?

Can't think of any reason not to do it.  There are millions of OEM vehicles on the road today with aluminum heads and cast iron manifolds.

 

11/29/2018 6:52 PM  #3


Re: cast iron manifolds on aluminum heads?

Other than losing a lot of the benefits of aluminum aftermarket heads by choking them with restrictive exhaust manifolds, there’s no harm in reusing the manifolds.

 

11/29/2018 7:07 PM  #4


Re: cast iron manifolds on aluminum heads?

A decent option might be a set of Hi-Po manifolds.  Quite a few re-pop houses are selling them and they are way better than a stock log manifold and are a good alternative to headers.  I'm running a set on AFR 165 heads.  I don't race it but it runs decent and doesn't exhibit any problems associated with the exh. manifolds.

BB


I have found the true secret of life....keep waking up!
 

11/30/2018 6:20 AM  #5


Re: cast iron manifolds on aluminum heads?

Bullet Bob wrote:

A decent option might be a set of Hi-Po manifolds.  Quite a few re-pop houses are selling them and they are way better than a stock log manifold and are a good alternative to headers.  I'm running a set on AFR 165 heads.  I don't race it but it runs decent and doesn't exhibit any problems associated with the exh. manifolds.

BB

On my laptop I have a article I think by Ford Muscle? Anyway they did a chassis dyno test on the same car, 67 with a mild 289 on stock exhaust manifolds, K exhaust manifolds and try y’s with the same exhaust system, 2”. The A&C code manifolds made exactly the same power as the K manifolds surprisingly. The try y’s made something like 15 hp more. Later on I’ll post the link.

As far as putting stock cast iron manifolds on aluminum heads, I think you’re really going to choke off the heads. What I would do is to use antisieze on the bolts and mating surface.


I'm not a complete idiot.....pieces are missing. Tom
 

11/30/2018 7:07 AM  #6


Re: cast iron manifolds on aluminum heads?

Use a good quality exhaust manifold gasket and it should work fine.  I wouldn't strangle those heads with cast iron manifolds though.  Get as decent set of shorty headers, something like the JBAs I run.  Then go 2-1/4 or 2-1/2" pipes all the way back with an X or H pipe (my system is a Magnaflow with an X pipe and 2-1/2" pipes).  The headers and exhaust made a big difference on a stock A code engine (Performer intake, Edelbrock 500 carb, otherwise stock).  That means the factory manifolds had become a restriction on a stock engine.  That tells me that on an engine with significantly better heads and cam the stock manifolds are a serious restriction. 

 

12/04/2018 6:34 PM  #7


Re: cast iron manifolds on aluminum heads?

Even with the hipo manifolds, on Edelbrock aluminum heads you will need to grind down part of the head so the manifolds will actually bolt up flat to the head.  DO NOT ASK how I know this, but if you just bolt them on and drive the car, you will have four huge exhaust leaks IF you don't crack the manifold trying to torque it down to the head.  The extra thickness of the head (deck thickness) holds the manifold away from the ports.  Not enough where you can see it, but enough for a huge leak.
Just be aware of the problem and grind for clearance.  I have not tried the stock manifolds with Edelbrock heads, but the hipos do have this fitment issue.


Money you enjoy wasting is NOT wasted money... unless your wife finds out.
 

12/04/2018 8:49 PM  #8


Re: cast iron manifolds on aluminum heads?

MS wrote:

Even with the hipo manifolds, on Edelbrock aluminum heads you will need to grind down part of the head so the manifolds will actually bolt up flat to the head.  DO NOT ASK how I know this, but if you just bolt them on and drive the car, you will have four huge exhaust leaks IF you don't crack the manifold trying to torque it down to the head.  The extra thickness of the head (deck thickness) holds the manifold away from the ports.  Not enough where you can see it, but enough for a huge leak.
Just be aware of the problem and grind for clearance.  I have not tried the stock manifolds with Edelbrock heads, but the hipos do have this fitment issue.

Same story with AFR 165's.  Required enough that I took some off the manifolds instead of all off the heads.

BB
 


I have found the true secret of life....keep waking up!
 

Board footera


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