I run the fan on the outside of the radiator with a thermostatic switch. It is a 2400 CFM fan, and it keeps the 261 cool in the local weather, which rarely hits 95 in the summer. For a 350 I would get a higher CFM fan, in the 3000 range. I put it in mainly for clearance reasons.

Paint & Body Shop moderator
A lone amateur built the Ark. A large group of professionals built the Titanic.