VancouverL71

I just got my rebuilt 427 back onto my frame. Someone suggested that the best exhaust manifold gaskets where the copper Mr Gasket style which I used for my steel heads. I have changed my steel heads over to AFR aluminum heads. Does anyone know if their would be any corrosion type issues when using dissimilar metals. In other words, are these still appropriate?
Thanks, Pete

Big2Bird

i wouldnt worry about in a dry location.
If concerned, I think the graphite ones are best myself.

VancouverL71

Well I live in Vancouver on the west coast of Canada which is about as wet of a place as you could ever imagine. Thanks for the response though, car will be in a heated garage and not out on rainy days.
I will check out the graphite ones you are referring to.
Pete

theandies

Get some Earl's, you can thank me later.




They do cost a little more but well worth it. I don't think you'd have any problems with copper on aluminum as I use a copper based anti-seize compound on my spark plugs into my aluminum heads. Dissimilar metals will experience electrolysis but it needs an electrolyte which is usually water. In this case with the heat at the point of contact water is usually not present or boils off quickly.

resdoggie

Why use copper when you can use laminated aluminium gaskets like Percy's? Mine don't leak.

HeadsU.P.

Just my opinion, but I think using header gaskets on exhaust manifolds looks awkward. Headers have a flange that hides the gasket the entire length of the head. Manifolds don't. You need six piece gasket set (three each head) for it to look right regardless of what material you use.

Go to Summit.com and click on gaskets > exhaust. But make sure you select "manifold" gaskets. See what options they have.

theandies

I misread his post and didn't comprehend he's using exhaust manifolds instead of headers.

Les

I just assumed he would be using headers if he spent the $$$ for the extra flow that AFR heads bring to the table. I'm not really sure if he's using "exhaust manifold" generically or if he really means he's using the old school manifolds.

OP, can you clarify?

gkull

I will give a vote for Felpro blue steel exhaust gaskets. Even with glowing primary pipes I have never had them fail

I use ARP exhaust studs. Never use bolts into aluminum heads

VancouverL71

Thanks for all the info. I am using stock type manifolds. My understanding is that some people suggest using no exhaust manifold gaskets but I got the impression that most people used something under the factory manifolds.

I have been very intrigued with Steve's build in Washington State with his blue 1967 convertible that is stock appearing with factory manifolds and the tri power and running 10 second quarter miles. I realize he is way beyond 427 CI.

I posted a year or so ago and surprisingly could not find anyone who had done a 427 build with AFR heads on a 1968 or 1969 and kept the original pieces and squeezed it under the factory big block hood. Thats my plan. Hopefully I don't run into too many issues. I may end up changing to headers down the road if I want more power but I like the to keep everything looking as original as possible.

So for now I plan to keep my tri power and use the factory manifolds and have hidden the AFR with orange paint to qualify for vintage license plates. I am aiming for mid 500 hp and torque. Thanks for the link to the Earl's type gaskets, they look pure quality. I will check the Percy ones as well.

Here is a picture of where I am at right now.
Pete

theandies

I have used bolts in my aluminum heads for years. A little anti-size works wonders. Never had any problems. I safety wire the bolts so they never come out. I guess that's the old aircraft mechanic coming out......lol

HeadsU.P.

This is what happens when people assume its a SBC or you are using headers. You tricked us all.

C6_Racer_X

Count me in the graphite gasket camp.

The Earls are great, but I'm not sure if they are available for the 427. Remflex is also good. Both are a little pricey, but well worth the money for the quality.

VancouverL71

Should have been a little more specific re my build. Those Earls gaskets do look amazing but C6racer you are right, I just looked everywhere and they seem to have discontinued the Big Block Chev version. (The small block is readily available)

I love that safety wire look Andies but If I was to try that it would look horrendous!

Thanks again for all the help everyone

Pete

427Hotrod

The Fel Pro graphite style work great. I've got them on my turbo set up with no issues. Been re-used several times.

You can also just use hi-temp silicone if you don't want gaskets showing and want it to look closer to stock. Turbo guys with mega heat and backpressure do it all the time and it works fine.

JIM

VancouverL71

Thanks Jim,
Everything else is Feldpro on my engine thus far. Not sure why I let an auto parts guy suggest the MR Gasket copper way back when. I will check out the feldpro graphite as well.
This forum is such a wealth of knowledge!

427Hotrod

I don't see anything particularly wrong with using the coppers. But silicone won't show if done nicely.

JIM

theandies

Lots of practice over my 15 year aircraft career. Most of the time I did it by hand but we did have safety wire pliers in our boxes. I still have some in my box.

scottjamison

When I got my 496 with Al heads from Blueprint, they flat out said only use copper header gaskets.

vince vette 2

That's interesting. On my wife's 84 Firebird V6 corrosion between the copper intake manifold gasket and aluminum manifold cause coolant to leak into the engine. Fortunately we caught it before it caused bearing damage. It was a common problem with those engines.



On the other hand, I have a 40 merc flathead V8 which was in my father's 32 Ford Roadster rod (which we still have) and it had copper head gaskets with a set of "high" (for the time) compression aluminum heads. It never seemed to bother them. Must be more to it than just copper, aluminum, and electrolyte.