That looks like a Craftsman 315.27802, 2.0 HP. 12 AMPS, 7" circular saw from the late 60s. Although it's advertised as a 7" saw, it will take a 7 1/4" blade.
This saw featured a detachable wrap-around sub-base for flush cutting. That part is missing from your saw.
I bought one of these last year for $10. Of course, the one I got is in very fine condition and complete. I use it most of the time instead of my newer circular saw. It works great.
Quite frankly, while I paid a "premium" price for my saw, you couldn't give me the one you have. Sorry.