Owners manual

This stems from reading a thread concerning Cherokee rear disc brakes on a vintage 8.25 rear. That reminded me of something...
Back in the 80s I made a deal with a nice older lady who worked the counter of a family owned auto parts store ( Zaglins ). If she would allow me to spend my lunch hour(s) flipping through her part books, I would let her fill my parts list. I explained my goal of placing 73 up A-body disc brakes under my 67 Barracuda.
While she was in gathering the parts per the list of numbers I provided she said, " I wouldn't want a car that had belonged to you". "Why is that?" I asked.
Her reply, "The next owner wont know what parts to buy for it".
She had a valid point then. I can't imagine what she would think of us today. Anyway...
I intend to give my red fish to my granddaughter on her graduation day. Without some reference to consult she might curse papa and this "rat rod" he gave her.
Has anyone else considered a supplement to their owner manual detailing what changes have been made to the car ?
Is the actual ink on paper reference the best plan ?