> Like any other older car, the lead was
> needed to lube the valve guides. Depending
> on the miles on your Z, most likely the
> exhaust valve guides are already shot...
> we've been unleaded for a while. The
> additives work well, but when you decide to
> rebuild, the machine shop will hook you up
> with some nice hardened guides.
What about the seats,are they already hard enough?
> The lead was not used to lubricate the
> valves it was used to help the valves seat
> and seal. The soft bronze seats needed the
> help. You will not be in any dire emergency
> to have the seats replaced, but if your head
> is off, a valve job and some hardened seats
> would not be a bad idea.