While all the fillers and baffles are good factory tweaks, I should point out my 455 runs all summer long at the temp of my thermostat (185) without the factory filler panels, lower baffle or rubber fillers installed (stripped down for paint eventually)
Did you tweak the divider plate on the water pump for a close tolerance like Bjorn suggests? A lot of people have found that makes a HUGE difference.
I am also running the biggest FB aluminum radiator that Rodney Red makes
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI