15 or 16 inch Radiator Fan with thermal Clutch?

[chevykevy]

I have put a 71-72 front cross member in my 64 and have a SBC in as well. Engine is in the forward position. Made an aluminum fan shroud thanks to posts on the site by folks who have done this before. Problem is that the engine sits low enough that the lower radiator hose would be hit by the fan if I were to use anything larger than a 16 inch fan, leaving extra room beyond the 16 inches as well.

I currently have a Flex a lite fan (16") without a clutch. Between the constant fan and the shroud I think I will have trouble warming the engine. I started the engine for the first time last weekend and it takes quite a while to reach temperature. I am in Wyoming and it is in the 30's. I resorted to warming with a piece of cardboard covering the radiator and that did get the thermostat to open and flow through the radiator.

I think a clutch fan would help warm up, highway noise and free up some power. Anyone using a factory type or other 15 or 16 inch fan with thermal clutch?