Golden Age of Drag Racing Ironheads

Many of You may have seen this Past Hot Bike spread on the Golden Age of Drag Racing that Covers a Few Bikes from ATCO 1969,
Note the Black Sportster of Mayne Price 'Custom Cycle Engineering' Paterson, NJ..
also Note that is Bob Mauriello in the Red Leathers-White stripe getting ready for a run on Mayne's bike, Mayne working the parts on a folding chair.. Mayne was a Super Talented Machinist and Drag Racer in his day, now retired in Pennsylvania,
More Ironhead History: if these are all 1969 pictures, note the notched Rocker boxes on a few of the bikes a full 2 years prior to the 1971 Production Sportster!
http://www.hotbikeweb.com/features/0709_hbkp_harley_davidson_1960s_racing/viewall.html