The seats were induction hardened to a depth of something like 0.005" deep. When you do a new valve job, this hardening will be lost, so you might want to press in hardened seats. I have run several heads without hardened seats on unleaded, and they hold up fine unless you get the engine very hot (225F+) or get into detonation.

Lou

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Home of Slant6-powered fun machines since 1988

As I understand it, that hardening is not necessary for the intake seats; just the exhaust seats because the intake seats don't get hot enough to need it... is that right, Lou?

Bill @ Conway, Arkansas

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1964 Valiant 4-door sedan, 225 turbo/904

I was afraid of that

Correct, Bill. Heat is much higher on exh valves/seats.

Lou

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Home of Slant6-powered fun machines since 1988

Somehow I missed a few posts here on this topic and I am a bit confused, it sounds like the valve seats were hardened when new but were not the conventional hardened valve seats that we typically associate within a head.

Not sure how I am going to handle my machinest and do not want to make any accusations about him not knowing what he is up against if its just a mismatch of terminology.

Can someone clarify

Thanks, Lou.

That's what I had thought.

Bill

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1964 Valiant 4-door sedan, 225 turbo/904

If it is worrying you then just have your machinist install new hardened valve seats.

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Casually looking for a Clifford hyperpak intake for cheap.

It is common to install hardened exh valve seats in old engines. Any competent machine shop can do this for about $10/valve.

Lou

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Home of Slant6-powered fun machines since 1988

I agree with both Lou and Reed (and Bill). Install hardened seats on exhaust only for security purposes.

Welcome aboard. This makes me want to buy an old truck.

Are the hydraulic cam systems reliable on the later slants?

Sam

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As Lou said, Factory "Induction Harding" was Ma Mopar's cost efftiveness with dealing with low lead/no lead in the 70's and will be lost during a head rebuild. That may be what your machinest refered to. Some of us that run old cars on a daily basis that are 50 years old now are still going strong with no ill efects. It's hard to kill a slant(though it has been done !)
If cost ($60) or so to have seats installed now is the time to do so while everything is apart.

Absolutely.

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Casually looking for a Clifford hyperpak intake for cheap.

Not worried, only trying to learn something new. Thanks

This thread helped me today.

I recently snagged an 86 slant out of a truck. It is an unknown quantity of the U-Pull-It variety. The plan is to clean it up and see what it looks like inside.

If it looks OK, I will probably change the oil pump and the timing chain while I have it out. SO much easier that way.

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1961, 1962, 1963 and 1965 Valiant 200. The `65 is a `vert.