Contributes to dad's conversion? (4)
I believe the answer is:
adds
'contributes' is the definition.
('add' can be a synonym of 'contribute')
'dad's conversion?' is the wordplay.
'conversion?' indicates anagramming the letters (I've seen 'conversion' mean this).
'dads' is an anagram of 'ADDS'.
'to' acts as a link.
(Other definitions for adds that I've seen before include "Aggregates or makes further remark" , "Sums, totals" , "Does summer job" , "Supplements" , "Puts in; tacks on" .)