Correct size fan and fan clutch

What is the correct diameter fan for a 1970 Dart Swinger 340 with A/C and the max cooling 945 radiator? I'm getting conflicting information. According to Paul Herds Chrysler Muscle Car parts interchange manual 1968-1974 the correct fan for my application is a 7 blade, 18 1/2" in diameter, and is Chrysler part number 2863216. Looking to confirm this information or find out what the correct fan and fan clutch is. Thanks in advance.

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From parts book on MyMopar
L = Dart..

Can I add to this thread since it seems to have paused. I have same type & part number fan #2863216 from my 72 Challenger. I was using it on my Duster w 408 and found a crack in a blade so need replacement fan. I find two aftermarket fans available and I don't need number match in moded Duster. Hayden 3618 or Flexalite 5718 which are both 18" 6 blade fans for clutch mount. Has anyone used either of those, do they fit stock clutch, and will they cool like stock fans.