OK! so here's another 440 overheating issue.

[1962polara]

Seeing that picture of the gunk inside your radiator reminds me of mine.I had it power cleaned but it still didn't clean it correctly.It was only when the top was removed and a thin steel rod was passed down each gallery that it was perfect .
hope you can work the problem out. Good Luck

 

[747mopar]

When I was putting my motor together I kept hearing a rattle when I turned it, found a frost plug in it that looked like it had been there a while. As far as radiators go I bought a Be Cool radiator at a scratch and dent sale that was tweaked, laid it on floor and bend it back and haven't had a problem (456 stroker, 165 thermostat, 16" thermal clutch fan and a good shroud).

 

[moparcanuck]

I did everything in the book to try to get my 440 to run below 200. Nothing worked until I put a 160 stat in it. You may argue that this is not right but it cured my problem.

 

[am3rican]

I'm curious to see if you got the problem fixed. Let me know. My fan shroud, thermal clutch, and fan are going on this weekend. I'll let you know if that solves my issue.