hardened exhaust seats

[ir3333]

had both '72 and '73 cuda and challenger back in the day...no problems and ran unleaded fuel.
...what year did induction hardened seats begin on 340?
...is a proper valve job good enough?

 

[valiant1966]

From what I have read, hardened seats started in 73. I think all cars were burning unleaded by 75(by law) and so manufacturers started getting ready early.
Will a good valve job make a difference? No. Many people argue about whether hardened valve seats are even needed. I have never personally had a problem with sunken valve seats nor have I ever even seen them myself. Only plenty of stories of them. Enough that I would tend to believe them. Dennis

 

[Abodybomber]

Not "hardened seats",as in hardened inserts. Induction Hardened seats,sound better. The top.020-.040" of the seat surfaces,were flame tempered on top. After a good valve job or two,gone. Ask anyone,who has seen some heads,equipped with early/mid 70's egr.

 

[340sFastback]

Here is my original 340 with x heads. These heads have 75,000 miles on them since they had a valve job back in the early 80s. No additive in the fuel and obviously none of the valves are sunken.

 

[1970Duster]

Always install them. I've had a pair of heads that had sunken valves. Nope deal with that crap again.

 

[DaveBonds]

75k is reasonable milage, but not high by any means, nothing I'd rebuild if everything checked out ok.

I will say, that when I opened up my 302s, the induction hardened head was fine, but the valves were spread and pitted beyond use. I think the induction hardening saved the seats. No idea on mileage. When I put stainless valves in, they checked out square.

Hardened seats are a good idea, especially with higher combustion temps/ 150+ cyl psi applications.

I guess it depends on how much milage you want out of the engine and what kind of heat they will see/ usage. Build it to fit the bill.

 

[ir3333]

...that was my thought,original heads with a proper valve job would probably be fine for
most.
...these cars usually see less than a couple of thousand miles a year.