[my56chevytruck]

I also have a 454 in mine, but I want to ask you a few questions. Overheating means to me fluid puking out, but it means other things to look at, is it in fact puking fluids? What temperature does the engine get up to? You can get for a few bucks a laser temperature gun and you will then know the accurate temperature your engine is getting up to. I'm running a 2 core, 1 1/2" tubes - aluminum radiator and an electric fan with an adjustable unit to come on about 170 degrees, and it runs fine. More tubes depending upon the sizes could mean a much wider radiator, do you have that kind of room and or it could mean much smaller tubes than say 2 or 3. Are you running a 50/50 mix?? Number of tubes doesn't necessarily correct an overheating issue. Others have also mentioned factors you need to look into if you already haven't.