the k20 is actually a lighter engine than the b18c as its all aluminium i heard.
a dc2r has been recorded as doing 13.9 to low 14s 1/4mile
an eg has shown time slips with high 13s on these forums.
im guessing a fairly stock b18c in an eg and ek will get similar times, around the high 13s.
and a slightly modified b18c will get u mid 13s.
k20, no idea