Octura engines?

Somewhere in my archives (e.g. mass of attic stuff) I have original Octura gas engine blueprints. I grew up in Niles IL, and his shop was down the road a bit from where I lived. Later, he moved to a small industrial park where I worked as a machinist.
Wandering into his shop one day, I talked with the owner and found out he had plans for engines he had designed ignition engines back in the...1950s?
I bought copies of the prints, and dreamed about making the engines for my use.
Looked briefly into getting castings made, and found out that the parts for an engine would run me about (1977) $12. Then I asked how much to make the patterns, and the man looked at the prints and said "Oh, about $1500".
EGAD.

SO put that on the back burner...WAY back....
Later I got a job as a pattern maker, so that solved the patterns problem....still never got around to make them.

Maybe some day.....