You know, when we run these small grille shells, the water capacity is sometimes compromised. Have you did the trick of running heater hose in a loop all around the vehicle or some sort of piping and hose and maybe a heat sink to aid in cooling/volume? How'd it do?
Nope, never tried that, but I noticed that adding oil capacity makes it take longer to get up to temp. On the same track you could also add an oil cooler as well.