Posted by casebro on Monday, December 23, 2002 at 1:30PM :
In Reply to: Re: Fuel posted by gtk on Monday, December 23, 2002 at 12:59PM :
I think there was a small window 60's-70's when the manufacturers used induction hardening to the parent head. Before this and after this, they used actually hard seats. So flat fenders are O.K.... and I wonder, when they came out with unleaded gas, didn't they also lower the octane rating of the fuel, causing pinging, which would pound valves into the head? (called'sucking a valve') soooo, the lead didn't have as much to do with valve life,it was the lowering of the octane without detuning the engines????