Something you have to be really careful about when adding hardened seats,is
getting into a water jacket. My race shop ruined a nice 049 oval port head
trying to do this.
Clint Hooper
H&H Custom,owner
LT5 Registry Director
http://www.LT5Registry.net/
ACES #1650
http://dalesplace.com/misc/friends/clint/clint_hooper.htm
----- Original Message -----
From: "Bill Lessenberry" <[EMAIL PROTECTED]>
>
> You're right, from what I remember (and it ain't what it used to be) the
> mid 70's heads were the first to have hardened seats. They were induction
> or flame hardened, I can't remember the exact process. The problem was
> that the hardened layer was very inconsistent; thin in some spots &
thicker
> in others. It's possible to grind right through the thin layer when doing
> a valve job. The seat recession problem isn't really widespread, but if
> you're going to the trouble to refurbish the heads, then why not do it
> right the first time & not have to worry about it? The heads may show no
> wear when torn down, then the seats are ground, the hardened layer goes
> away, then the valves sink, & you have to do the job over & install the
> seats. More time & money spent. Or just buy the lead additive or pour a
> pint of Marvel Mystery oil in the tank when you fill up.
> Just my $.02
>
> BL
>
>
