The especs for these might help:
The hot rod F7 is no slouch, it will wind out to a bit over 350mph. (still needs more)
<kuid2:999999:2222:1> 1 Hot Rod Special F7
The cow rocket puts it to shame with a top speed of 895mph but it's not very responsive in cab mode.
<kuid2:217537:103:2> Cow Rocket