451 overheating, even when moving

I'm just gonna say this and you glean from it whatever you want. The stock Mopar cooling systems cooled everything from slant sixes all the way to the 13.5:1 Max Wedges and the 12.5:1 Race Hemis. The NEVER RAN HOT with STOCK Mopar cooling systems. You might want to consider that a CLUE.
Makes a lot of sense, but gotta work with what I got due to $$$ :(