[Logan]

Take a 3 inch sander with 36 grit paper to grind the junk and paint away from the weld, be sure to get it really good where it's leaking. Then scratch the area around the crack with sand paper or grey scotch brite. Spread the jb weld, then take wax paper and spread it over the jb. This will allow you to smooth out the jb while it's wet, and it will look really nice and smooth when it's done. Once you have it looking the way you want, remove the wax paper and it will dry how you want it to.

You're heating problem could be you're water pump isn't turning inside the head. Could be a broken shaft towards the back. Could be a plugged block or radiator. You also haven't told us what temp you are considering hot. I wouldn't start worrying temp wise until about 190-200. Then to hot will be 210+. Remember obviously the water coming out the bottom will be quite a bit cooler than the top water. I would get a clear hose and make sure the water is flowing well from the block to the radiator if you are really concerned and over hearing bad.

The clutch just seems like you don't have the clutch arm properly adjusted. Unless you just have some horribly damaged gear, idk why else it wouldn't go into gear. Try putting the car into second, start it with the clutch in and then take it for a test drive. But just make sure your clutch arm is adjusted properly.