The owners manual for my 73 states you may use both leaded or unleaded. The production date on the vehicle is 11/72. Not sure of the casting numbers or if this version of 440 was used across the board in other Mopars. Tim --- sosmi@xxxxxxxxxxx wrote: > According to DAS BOOK, hardened valve seats, came > out around 74, the casting #3769902 the 73, 400-440 > motor home castings 3751213, could also have > hardened seats.The castings, > 3769902,3769975,4006452, all have hardened > seats.Ya'll have a nice day, Dave. > > -------------- Original message -------------- > From: aeyn <mr85000@xxxxxxxxx> > > > Regarding this subject. > > Does any one recall when Chrysler started to put > the hardened > > valce seats in the engines. I remember something > about they > > started gradually putting in the hardened seats > PRIOR to 1975 in > > differnet model lines. > > > > ƹn. > > > > > > --- Dan wrote: > > > > > There were a number of posts recently about lead > additives but > > > I don't > > > remember anything about "amounts per gallon". I > followed the > > > directions on > > > the product I bought of 1/2 ounce per 5 gallons. > Considering a > > > half ounce is > > > such a small amount, does this sound right? > Also, can someomne > > > tell me what > > > might happen toa 440 or 413 if it is run with > premium unleaded > > > gas and no > > > lead additive? If it is harmful, would it be > immediate or > > > gradual over time? > > > > > > I'd also like to join in with thanks to those of > you who fought > > > for our > > > freedom. The character and courage of men and > women like you is > > > responsible > > > for the freedoms we all enjoy today. > > > > > > Thanks You! > > > > > > Dan Collins > > > 67 Crown Coupe > > > > > > > > > > > > ----------------- http://www.imperialclub.com > > > ----------------- > > > This message was sent to you by the Imperial > Mailing List. > > > Please > > > reply to mailing-list@xxxxxxxxxxxxxxxx and your > response will > > > be > > > shared with everyone. Private messages (and > attachments) for > > > the > > > Administrators should be sent to > webmaster@xxxxxxxxxxxxxxxx > > > To UN-SUBSCRIBE, go to > http://imperialclub.com/unsubscribe.htm > > > > > > > > > > > > > > ----------------- http://www.imperialclub.com > ----------------- > > This message was sent to you by the Imperial > Mailing List. Please > > reply to mailing-list@xxxxxxxxxxxxxxxx and your > response will be > > shared with everyone. Private messages (and > attachments) for the > > Administrators should be sent to > webmaster@xxxxxxxxxxxxxxxx > > To UN-SUBSCRIBE, go to > http://imperialclub.com/unsubscribe.htm > > ____________________________________________________________________________________ Cheap talk? Check out Yahoo! Messenger's low PC-to-Phone call rates. http://voice.yahoo.com ----------------- http://www.imperialclub.com ----------------- This message was sent to you by the Imperial Mailing List. Please reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be shared with everyone. Private messages (and attachments) for the Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm