Thanks for everyones input, its greatly appreciated. Im hoping techinspector1 or someone else here could possibly answer this question for me. Im wanting to know what my rebuilt long block came from originally and dont really know where to go. I do know that its a 64-67 era 327 but I dont know what its H.P. was, what kind of vehicle it was in or anything. Maybe you can help me. Also (Techinspector1) would these numbers designate exactly what harmonic balancer/dampener I need for a stock application without having to do the previously descibed methods you posted?
Here is what I have-
Block Casting # 3858174
Engine I.D.#/ VIN CODE FIII7YC
Heads Casting # 3884520

Any more identifying help is greatly appreciated!