Hardened valve seats

[Oztrailer]

Saw a Mach 1 for sale on ebay and the seller made this comment......." Engine was built in 1972 with hardened valve seats and guides as ULP was introduced into California on 1st Jan 1973."

Does anybody know if this statement is true?

[snellet]

I Believe it is. I read some articles a couple weeks ago when I was trying to figure out why my mach was running rough and they said the same thing.

[Steven Harris]

Steve O,

I was reading on that specific topic last week and the consensus was that the change to hardened valve seats was in 1971 / 72. It would seem correct that for California it would have happened by 1972.

[snellet]

From what I read, it was started in 71/72 and fully implemented in 73. There is however, differences in opinion on different sites

[Oztrailer]

Thanks for the replies, was it a country wide thing or just certain states?

[Steven Harris]

This is before "my time" as I was still in Africa but the move to unleaded fuel was countrywide. I am not sure of it's implementation. Usually California pushes the envelope of EPA measures and eventually the other 49 states follow suit by federal mandate.

[keith1562]

This is before "my time" as I was still in Africa but the move to unleaded fuel was countrywide. I am not sure of it's implementation. Usually California pushes the envelope of EPA measures and eventually the other 49 states follow suit by federal mandate.

my brother bought a bone stock 1972 sprint sportsroof. It was designed for unleaded fuel only. We had to use a small plastic adapter for the leaded fuel that was not meant to be used in this car.

[gxr02190]

Never heard of hardened valve guides, just the valves.

[furray]

Me too, no guides just seats. If it's had seats put in it ( the right way ) would be a virtue, not a deterrent.