I've got a 351 Cleveland, I put a 170 Thermostat in and it runs around 190 puuuurrrfect!, I've got a triple core radiator and no need for an electric fan. All it would do for me is restrict air flow and plus I already have the engine fan. I'd ditch the fan, but thats just me. Good luck. By the way what kind of 351 do you want?

my two cents.