the 440 cooled OK with the same rad/fan distance/no shroud? did the 440 have the 'source alum pump? If no on the pump Q reportedly iirc there was a run of restricted 'source pumps way back which has been resolved. a quick pump housing swao including the pump itself if it is a scroll type would ans that. What Ahy said #1-air. I'm assuming same pulley ratio. If it ain't the pump/housing I'm not grasping what is different unless it is the eng but OK at speed pretty much elims the eng & points to air or water speed unless the timing is too retarded at the RPM's it is running hot at