I’ve started a few jobs on the older 12 (8D) because I am still waiting for various items that are stopping me from starting the 8XE. It will be a side project until I get the other assorted bits back.
I got this great frame from Dewey Rice. It comes complete with the the top motor mount that will need attaching later. First job though was to drill holes for the lower mounts. We laid the frame on wooden blocks and supported the motor front side with blocks to keep it parallel to the down tubes. The top holes were drilled first (slightly undersized just in case) and then the motor re-fitted. That done we set about the lower two holes. Straight forward and simple. The bolts shown are just some we had on the shelf. We will look at the top mount in the future.