to add to the last post: the older A-4's had passages cast into the cover plate on the water pump side of the motor and are known to scale and cause flow problems. Universal changed this and added a steel plate with a directional valve to shoot the water aft, Moyer sells these. It's not a hard project but you will have to remove the pump to bypass and bypass to t-stat lines. the alternator and bracket. I was able to get mine off without removing the starter, had to, the bolt heads were wasted. You got the right idea, take it one item at a time up stream. Oh, I highly recommend the FWC I have one in my '77 Ranger and inside of the engine and manifold was impressively not deteriorated.
Ahh, how old is your sister???