Contact SUM fan company and do some CFM research, and you want a "Puller" NOT a Pusher. Anything including a pusher fan in front of your radiator will block air at speed. You can wire it with some form of thermostat or with an on-off switch. Either way will work, the on-off switch requires a bit more "tending" Talk to their tech people. Talk to Summit racing tech people. You will probably will wind up buying it from Summit anyway and their good folks to deal with. Do the measuring you need to before you call. East to West, North to South and the depth from your pulleys to you radiator. If you do it right you will not need a clutch fan at all, Jer
If I go this route, ditching a fan drawing torque/power off my engine will be THE goal, along w keeping said engine cool. Ergo, dropping the pusher in favor of 1 or several electric pullers will be part of the upgrade for the exact reason you gave. For the present, a pusher serves Mathilda well, given the rarity of highway travel we have.
I will first upgrade the alternator before implementing any such plan. I want PLENTY current available to an electric cooling system, especially one which would be meant to completely supplant the traditional mechanical system. I like the Moroso kit with bracket and DC motor meant to drive a mech water pump. This allows an easy retro-fit back to belt drive off the crank pulley should the DC motor fail. Ideally, I would prefer to use a variable speed DC pump motor, calibrated for volume flow appropriate to temperature, and attach such to the Moroso bracket.
W a little extra $, I'll get a good thermostatic switch to provide a ground path for the fan relay, which then can be paralelled in with the toggle switch I use for the present. I LIKE having ultimate control over these basic engine accessory functions. I use a manual choke with my Stromberg WWC 272 carburetor which avails in all sorts of situations in which a standard stove-top spring setup won't. Mind you, any electric water pump MUST be running at a decent speed for basic cooling, so I shan't toggle such if installed.
All these speculations at present are just that. I need $$ to make this stuff happen, and only after more vital projects like a new timing set and distributor, dual pot mech master cylinder.
Then Summit, who like JEGS and Speedway and of course Rock auto all have received my custom may do so again.
But there are NO BETTER forums for my speculations than this one, and no better folk to revolve such thoughts about with.