Keeping opinions aside, please know that if you go with the radiator Eric suggested, you will need a different lower radiator hose. I believe it comes from that same vehicle.
Facts that I have learned working on hundreds of these cars:
The coolant elbows you "upgraded" are actually a downgrade. Years ago GM included the lower elbow into the alternator bracket (you called it a pulley housing). This cast elbow had a nice o-ring on it and GM started seeing a problem and quickly changed to two nylon elbows. The aluminum cast piece would corrode and when someone attempted to remove it, they often broke the timing cover where in enters. A nylon elbow can be wiggled easier in all directions as it has give. If necessary it can be broken and then removed as pieces. Those aluminum elbows, I have seen one break, they aren't super thick and beefy as they appear. Hopefully they don't corrode and cause broken timing covers, it is my hypothesis that they will.
The Caddy radiators are able to be swapped into Bonnevilles (92-99), honestly I doubt you'll get enough benefit from an all metal radiator to be worthwile, but that's my opinion.
