I mounted an expansion tank that has a pressure cap on the front side of the water pump. I did this when I had the SOHC engine in my car but it still works great on a standard SBF. Makes it easy to fill and check the coolant level, oh and looks great as well. The mount is just a piece of SS sheet that goes down to 2 or 3 water pump bolts and has a simple brace back to an intake manifold bolt. I do also have an overflow tank so it catches any coolant that gets spit out of expansion tank.
I seem to recall that I bought the expansion tank from Forte when they were selling a lot of FFR related parts. That was many years ago so I don't know if they still sell this style tank.