Originally Posted by Mike Voth (Post 94163)

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!!

Originally Posted by Mike Voth (Post 94526)

C-11 is a more application specific blend. Works better in lower compression applications with restrictions in air flow. I know a lot of stockers that use it with small blocks and big blocks, as well as super stockers. It burns more efficiently than C-12 and generally makes more power, overall. But I'm sure people have experienced different results. That's just what has worked for us with our 327 in super stock.