Mancini racing custom fabricated rad(worth every penny) with a mopar performance water pump and viscous clutch fan package on my built 340 'Cuda. Originally I thought it ran at a constant 180*, but I had a defective sunpro water temp gauge, so I swapped it out for an autometer. My car runs consistently at 165-170* turning anywhere from 3000-3500 rpm going down the road in 90+ degree temps.