If it's the same RON+MON/2 octane rating, that fuel should be OK for street driving. Run the straight 100 for racing, even better if you can find some 100LL. I'd go with the less aggressive timing, just to be safe for the street. "Moar power!" is never really a big block issue on the street unless it's a really sick engine or something is very out of scope in the build. S/F....Ken M
