I wonder where the guy who built that site got his numbers for the density range of gasoline. I bothered to look it up in one of my books and got 7.4 lb/gal for premium unleaded (Forced Induction Performance Tuning by A. Graham Bell, 2002). When I checked the physics hypertextbook online I got 803 kg/m^3 and if I did my arithmetic right that converts to 6.7 lb/gal. Further investigation reveals that pump gasoline density has been changing as additive packages change to meet emission demands. I've also got some questions about BSFC assumptions that were made but right now I've got to go to class. Interesting topic Defiant!