Heat is more HP related as opposed to cu in related. Even if you were at 500hp a 3 core 22" radiator will do just fine. The highest HP numbers are usually above 5000rpm and your cruise RPM will be in the 300hp range so I wouldn't sweat it.
A lot of heat is developed by cam profiles uin combination with a stroker kit A long rod motor will dwell more on top of the stroke for a chance of detonation if the cam grind doesnt have enough overlap to bleed off some cylinder pressure.