X2011 slipstream 700mph+ Route X Gearbox settings

[ZedMan1996]

GT5 and 742mph+ (The sound barrier)

I've been looking for months on how to get my gearbox's top speed to over 700mph+. My current gearbox's top speed is 620mph. I need to know the gear ratios ect. Also post your own gear ratios and speed records here. Thank you. PSN ID ZedMan1996 (If my friends list is full, send me a message)

 

[dr_slump]

I thought it's 760mph at sea level

 

[ZedMan1996]

Do you do speed runs at route X with the X11 using online slipstreaming? Can you help me out with my gear ratios. My top speed of my gearing is 620mph. I need a gear ratio over 750mph. My current speed record has been 618mph but I hit that speed four times so far and cant go higher due to my gearing.