Re-read his post, he's not using a clutch fan, just a fixed fan. Adding a clutch isn't going to help anything. Try some water wetter while you're at it, I did have a car that was overheating and it did help keep the temps under control better until I got the actual problem dealt with.

I don't know how much air a 7 blade fan pulls, but I know my 4-blade(with no shroud) pulls a ton of air and keeps my 440 cool. If your cooling system isn't flowing enough, all the practical airflow through the rad you can get at idle isn't going to solve the problem.