Hyde,
I got one of those last spring.I have/had the same cooling problems after changing from a Ford crate 392 to a KC 418w.
I found that my VDO tempt guage reads 10* high.That is with the engine running.If I turn off the engine and then switch the key to ON without starting the engine,it reads correct.I changed senders,same thing.
Still runs too warm,just not as bad as I was thinking.