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1972 Chrysler 440 - Need Leaded Fuel?

Mopar went to the hardened seats (for non-leaded fuel) about 1974. If your motor has been living without lead additives for some time, then it either doesn't need it (which I've heard is true) or the damage has already been done.

Jeff
 
I had a valve job done on my 1971 Chrysler 440 last year, and the motor had been runing unleaded gas for more than 2 decades. I had them put in hardended valve seats 'just in case', but the machinist said the old valves & unhardened valve seats had no signs of damage from running unleaded gas. As for the octane and knocking: The 440's were fairly low compression to begin with, so knocking is not usually a probelm so you should not need lead for that. Also, the ethynol they keep sneaking in there, actually increases octane. Ethynol has less energy per gallon than gasoline, but it actually makes octane go up when mixed with gasoline.
 
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