I'm not sure what the fastest jet is, but Keith Zellmer of Z-Axis Racing held these records on gas in the last couple of years:
International Hot Boat Association (IHBA) Records
IHBA Division 1 Pro Gas Jet E.T. record holder at 7.81 seconds
IHBA Division 1 Pro Gas Jet MPH record holder at 133.08 mph
IHBA Division 2 Pro Gas Jet E.T. record holder at 8.17 seconds
IHBA Division 2 Pro Gas Jet MPH record holder at 133.08 mph
National Jet Boat Association (NJBA) Records
NJBA Pro Gas Jet E.T. record holder at 7.72 seconds
NJBA Pro Gas Jet MPH record holder at 133.67 mph
I'm sure that there are some much higher numbers for the fuel guys, but these numbers are pretty impressive! I'd be happy with them!!!