I'm suprised, even before the shroud mine never really overheated, just got right up there [mind ya it never gets to 100 here

] .... you're not overfilling the rad are you? needs to be down maybe an inch below the neck - also with the good new rad you can run a 12-14# cap, higher pressure allows higher temps .... can't help thinkin there's some simple solution, 283's "like" being hot
Bill