It does not look like a Case to me.
I think it is from Model Supply out of Chicago.
They were offered in 1/8 hp, 1/4 hp, 1/2 hp, and 1 hp.
You are missing the cast base at least in your photos.
Find the drawings. They will tell you more and make the kit worth more.
I have had a few of these over the years.
Gil
There is one in this video: