Joined: Nov 2016
Yadkin's right. "numbers matching" is more of a GM thing. There are date codes stamped into the block that will tell you when it was made, but even the same casting number for an engine block was used for multiple vehicles. A casting might show that it was made for the "Fairlane", but got used in Galaxies, Cougars, Mustangs, and Falcons too. Ford didn't stamp serial numbers into them.
Even if you are concerned about the car's value, many times going with a more modern 5.0 roller cam block will actually increase the value significantly to someone that wants to drive it. I wouldn't do that if you had a K-Code or Shelby, but it makes sense for a car that's not a museum piece or trailer queen. It is possible to retrofit a roller cam into an early block, or even make a flat-tappet cam engine survive on modern oil, but both options have drawbacks.
Typically, if your engine is overheating rapidly, it's one of three things. It could be problems with your cooling system (pump not working right, hoses collapsing, clogged radiator, scale in the block). It could be a blown head gasket (which produces some pretty spectacular overheats, usually along with puking a lot of coolant). Or it could be your engine's not tuned right - especially ignition timing. Since your timing's very suspect right now, you need to find TDC mechanically and verify your marks for the damper. Then when you KNOW where "0" degrees is, you can set things correctly. If you are over-advanced, it will make your cylinder temps WAY hot and cause all sorts of overheating and damage. If you're running retarded, you'll be blowing still-burning fuel out your exhaust and make the manifolds and exhaust really hot. Getting your timing right is critical.
Is your engine actually burning oil? Or did it just happen to have oil on the threads? Because that wouldn't really be so weird.
I hope this turns out okay for you!
I smile a lot. It makes people wonder what I'm up to...