360LA Clutch Fan

If you have a "bit of a cam" in that 360, I highly recommend to NOT run a flexfan, on account of, I have not had any good experiences with those. Every time I use one of those, I have cooling issues.
Your results may vary.

If you decide to run one; NEVER rev the engine up while your body is in line with the fan, in such a manner, that a busted-off blade could cut you in half.

And besides all that, I've also never had success with running a straight viscous-only clutch.
I switched to a Thermostatically controlled viscous clutch, on a large diameter, all-steel, 7-blade, fixed-angle fan, many years ago, and have never been sorry.
It may be more than you need, but when it comes to cooling, the cost of a melted engine is not something I want to think about.
And yet more besides all that;
If you are concerned about power-loss;
on the street, in a lightweight-A, with street gears, street tires, and a 360, I doubt you would ever feel a power-loss from a direct drive fan, with 5 fixed-angle blades. Your 360 already has a preponderance of power until the top of Second gear, after 80 mph or so; how often are you gonna go there? On the street, powerloss is not a concern ...... but overheating in traffic, idling along in gear and waiting at stoplights, is a concern.
And that is, just my opinion.