Can someone tell me where to look on this tractor so i can positively identify the model,engine,year for this tractor?. Oliver is in big letters with Hart Parr underneath in small letters located on front . has front starting crank with rear pto.
If  this happens to be a (1934-37 ) 18-27 would an engine from a 1938 Oliver 80 standard ( Hercules or Waukesha) fit into this frame ?

Need to ask lots of questions , restoring with my 18 year old son .

Thanks and looking forward to some replies.