Ford used them in the FE engine series, 60's for sure and maybe back into the 50's.  My books are at home so I can't  look it up right now. I used to have some for a 427 Medium Riser I was building before I switched to the slower side of life.

Mark in AK

----- Original Message -----
From: don spence <dkspence@TELUS.NET>
Date: Wednesday, November 1, 2006 1:35 pm
Subject: Re: AMC heads (part 2)
To: vanagon@GERRY.VANAGON.COM

> John/Neil
>  If I remember correctly, the Corvair engine, at least the 140HP (4
> carb) and 180 HP (turbo) had sodium cooled exhaust valves. Just
> another bit of "engineering advice" GM picked up  from VW?
>
> On 1-Nov-06, at 1:35 PM, Automatic digest processor wrote:
>
> > Date:    Wed, 1 Nov 2006 11:08:13 -0600
> > From:    John Rodgers <inua@CHARTER.NET>
> > Subject: Re: AMC heads (part 2)
> >
> > Neal, interesting post!
> >
> > I never knew that the V-dub engines had sodium filled valves.
> > Interesting info.
>