75 - 85 fl-lbs is listed on the Vanpelt website.
http://www.vanpeltsales.com/FH_web/flathead_torquespecs49-53V8.htm
In the Ford engine repair manual for 1937 1947 Ford V8 engines it is listed as 65-70 ft lbs,I would imagine that didn't change for later engines or flywheels.