Car's part in epic finish (3,3)
I believe the answer is:
big end
'car's part' is the definition.
'big end' can be an answer for 'part' (I have seen 'Part of engine' mean 'big end' so perhaps 'part' could also mean 'big end'). I'm not sure about the 'car's' bit.
'epic finish' is the wordplay.
'epic' becomes 'big' (similar in meaning).
'finish' becomes 'end' (synonyms).
'big'+'end'='BIG END'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for big end that I've seen before include "Dramatic finale" , "favoured by Blefuscudians" , "Part of the connecting rod in a piston engine" , "Car engine connecting rod crankpin joint" , "Connecting rod's larger extremity" .)