Help with radiator

The info on water pumps is a bit sketchy. Nobody has seen an engineering report from the designers, so we must speculate. Most AC cars had a 6-blade w.p., while non-AC got an 8-blade. Sounds backwards, but in both cases they wanted optimal cooling. The difference was likely because the pulley diameters varied between AC/non-AC. Therefore, more blades is not necessarily better. More flow will always give better cooling, but the pump spinning faster may not always give more flow (cavitation, etc).

I'll throw out another "far outlier". It is possible to install a Magnum timing cover on an LA engine, but that would make the water pump not work well since Magnum covers have vanes to direct the flow, but for the water pump spinning the other way. If you did change the timing cover when you changed the radiator, then "only thing changed" claim is getting weak.