I may be able to help you with this. I have a 2 page parts list dated Nov. 1983 with the notation "see drg. 90047"
I've scanned it to PDF and can email it to you. Just PM your email to me and I'll send on its way.
I have a set of Coventry compound castings and prints that I picked up from Cole's several years ago. It will be a few more years until I get around to starting on them so I can't vouch for the accuracy of the prints. I would be interested in hearing what you come up with for errors.