[trmnatr]

Originally Posted by Mike Voth

Right. C-10 is unleaded, so unless you put hardened valve seats in the heads, you'd be asking for a lot of trouble! Like micro-welding the valves/seats. Also, replacing the seats to run unleaded fuels just makes for the possibility of the seats coming loose and causing another big headache. Leaded fuel is the way to go, and until the government says otherwise, we'll leave the unleaded fuels, like C-10, for someone that doesn't BEAT the valve seats nearly as hard as we do!!

How does C11 compare to C12?

I use C12 but not in SS