the poly 318 was from 1959 i believe till 1966.after 1967 it is what we know as the LA motor,,

the poly head uses a staggered valve set up, some parts are interchangable to the LA,, oil pan i believe and dizzy,,same timing cover i belive.

go to allpar.com you can read about it there,,,

i have always thought these motors put out more power then a LA type 318,and there seems to be a ton of intrest down under,,also i believe you would find some poly 318 guys on the H.A.M.B.

not to be confused with the early poly motors of the mid 1950s, totally different blocks,,