Lucky you .....I have just sweat blood over the last few weeks on this very subject and have agonised buying 5 radiators to try and get one that fits right. Well finally only just today I have come across the solution...one which works. You need a light, thick cored alloy radiator which has the upper hose to the left hand side, which then enters the engine on the thermostat side and the lower hose enters the engine on the exhaust side. The radiator needed to be cheap, easy to get and will do the cooling.
And the winner was....
VN Series 2 to VS Commodore
Right size width and height, light alloy and thick core big cooling capacity and cheap!!!!