Timing Cover

I've had some issues on the '63 re-built 389.  Because an 11 bolt water pump and timing cover was used on it, I have not been able to find a pulley that will work with the original accessories on the engine.  I decided that I would put an original '63 389 4-bolt water pump timing cover on it.  The one that I had came off of a 389 that was pretty sludged up, but purportedly low mileage.  The cover, made out of aluminum, was chemically dipped while some other loose stuff I dropped off was acid dipped.   The progression on the water cover looks something like this: