I haven,t built a race motor, or raced a car since 1980, until now, so this thread is very interesting.I remember using Sunoco Cam 2 racing fuel, with great results, in a 13-1 big block Chevy.(not to be confused with Sunoco 260 premium pump gas). Does anyone here remember the octane rating of Cam 2? My current race motor is a 13-1 Mopar big block w/a solid roller.Trying to figure a safe starting point. Thanks for starting this interesting thread Doc Fiberglass. Bill