40 spark plugs. Less than 50 street miles on each. Went with a cooler plug.
$100 plus shipping.
Original Post
...You have the Perfect Sparkplug for the 351 Cleveland 'Autolite 25'. I have run ALL 3!
Just Like 'GoldyLocks', 24's are TOO Cold! 26's are TOO Hot! Autolite 25 Is Just Right!! Too Cold=Can't 'Blow-Off' the Black Soot, doesn't clean itself, 'Darkly' stained Insulator. Too Hot=The Center Electrode, Melts, Insulator is 'Blasted' White-Unstained.
I Gap them at .045", TOTAL Advance 36 Degrees BTDC @3100 RPM, CR 10.6:1
I ran the 25's in the Desert where the Ambient Air Temperature was 118F. Never had a Stumble, Pinging was never a Problem on 91 Fuel.
MJ