My fan's viscous coupling has started making expensive noises so I am thinking of going the electric fan route instead of replacing the coupling. I have a little 10" pusher fan now but if it is the only means of cooling I reckon I would go with the largest fan that will fit(15"?) with a thermostatic switch w/manual override. Summitt seems to have a great selection and their prices and delivery are usually excellent.
Richard
1975 TR7 ACL764U