Drive from Missouri to the heart of Florida (5)
I believe the answer is:
motor
'drive' is the definition.
(I know that drive can be written as motor)
'missouri to the heart of florida' is the wordplay.
'missouri' becomes 'mo' (abbreviation for the US state).
'the heart of' means to look at the middle letters.
The central letter of 'florida' is 'r'.
'mo'+'to'+'r'='MOTOR'
'from' acts as a link.
(Other definitions for motor that I've seen before include "Make good progress" , "Car; travel quickly" , "Car (colloq,)" , "Engine - relating to movement" , "Travel by car, engine" .)