-----Original Message-----It is the seats in the heads which were hardened. I don't know if they changed the valves themselves. I know that the 452 casting B and RB heads from 1976-1978 had hardened valve seats. Not sure about heads before that.
From: mailing-list-owner@xxxxxxxxxxxxxxxx [mailto:mailing-list-owner@xxxxxxxxxxxxxxxx]On Behalf Of Frederick Joslin
Sent: Thursday, March 09, 2006 7:34 AM
To: mailing-list@xxxxxxxxxxxxxxxx
Subject: Re: IML: Unleaded or Leaded gas
----- Original Message -----
From: clgilleland@xxxxxxxxxxxx
To: mailing-list@xxxxxxxxxxxxxxxx
Subject: IML: Unleaded or Leaded gas
Date: Wed, 8 Mar 2006 00:36:57 -0600
Hi, I was wondering When did Chrysler start putting hardened valves in engines so they could br ran on unleaded? I have a 74 Imperial with a build date December of 1973.Fred Joslin