Unleaded Gas In Old Engines (Non-hardened Valve Seats)

[parkerswede]

I have a 1970 Ch___ (well, its almost a Charger) with the original 350 engine in it. I don't drive it very often. I run unleaded out of the pump in it. Someone suggested it would eventually need hardened valve seats in it. If I don't drive it very often (68,000 original miles), will this be a problem? Thanks. P.S. I have a Charger also.

[resq302]

IF you don't have the hardened valve seats, you could just add some of that Lead substitute additive.

[Chryco Psycho]

generally the exhaust seats will erode over time without hard seats installed

[SirNik73]

wish i would have taken pictures, but a guy in my engine class was working on a set of 350 fuely heads where the exhaust valve had carved its way up into the head by about 1/4 of an inch.
the exhaust valve gets around 1300 degree, a dull red, only degrees from liquid, with lead in the fuel there was a layer of carbon that would build upon and stay on the valve face, and when it closed it would keep the valve from contacting the seat. but when you take the lead out, the valve makes contact and will actually weld is self to the seat for a split second before it is ripped open. repeat that a few million times over the least 30 years and you will have horrible valve seat recession.
the hardend valve seats from the factory in most cast iron heads is not a true hard seat, but instead the valve seat area has had the iron tempered to prevent this welding, problem is that the tempored iron of the seat is only good for maybe 1 valve grind. then you are down to the soft iron again.
if you are going to get a valve job, pay a little extra and have them insert hard seats. they will last as long as the engine does, if not longer 

[deathcharger71]

i rebuilt my 67' 327 and the exhaust seats were pitted big time, engine had little wear everywhere else but those exhaust seats and i lost a LOT of power because of it. we used lead additive for a while but it eventually needed the new seats. so basically yes youll eventually need the seats, and youll probabely notice and increas in power 

[TylerCharger69]

They will eventually carve up into the head...especially if you  stomp on it a lot.  The lead in yesterdays fuel provided a "cushion" so to speak between the valves and the seats.   There are additives you can add to the fuel to restore those properties.

[deputycrawford]

I used the lead additive for awhile and pounded the exhaust valves into the seats quite a distance. The lead additive is pretty much worthless in my book. Spend the money in the seats now instead of the tow truck later.