The base bike is a CB750K (k6 I think - need the numbers to verify the year). It looks like someone used a brit bike front drum on the bike replacing the disc (Looks like my old norton drum but I can't tell). There are a lot of nonstock aftermarket items on the bike (seat, levers, airfilters, etc) too, and some homemade items (like the left sidecover).
Hope you are planing to rebuild it because it looks like a death trap to me.