318 and 833 swap into 72 sedan

I'd stick with a stock fan set up. How wide and what is the condition of the existing radiator? You will need an a833/727 yoke for the drive shaft. Is your car a 3 speed now?

If you are driving even moderately bad roads, over speed bumps, odd/steep incline/decline driveways then avoid all headers accept TTI and Doug's.