rebuilding heads /383

[proud_owner68]

I wasnt sure if I have to replace the valve seats in my 383 engine heads.  Somebody told me that if they were not "hardened" seats they will not be able to hold up to un-leaded gasoline?  Im not sure when they started using unleaded gas, so I thought I'd check here to see what anyone thinks.  Im sure most of you who have running chargers will already know what type of gas you put in 

[dodge freak]

Oh my god I must be old. There was no unleaded gas in 1967. In fact it was not until 1975 before the new cars needed to use unleaded gas. I think around 1972-1973 the heads started coming with harden seats. Now about your heads if the motor is running fine and you do not have 4.10 or so gears in back  or are driving 80 mph on the freeway everyday for hours, I would just not worry about it Sure the valves may sink in the head and hurt the flow but those are just ok heads and you could always replace or repair them later on. If you are rebuilding the motor and are getting the heads done you might want to see how much it cost and compare with heads that already have them. It take a while to hurt them but leaded gas has been gone for a while too. In Michigan it was gone around 1990. You know what, somebody may have already put harden seats in it 20 years ago.

[Chryco Psycho]

I always have hard exhaust seats installed

[AKcharger]

You may end up driving it more than you think...I've already put 10K miles on mine since rebuild. I think the seats are $200 and around another $200-250 for machine work. I bought a set of 452 heads last Saturday for that very reason. Oh, 452's are the later heads with hardened valve seats from the factory

AK