According to an article on Weekly Puroresu, DeFazio and Jackie Nichols trade the title four times, but Nicholas' reigns have not been confirmed; vacant in 72; some reports have title being inactive after Bruno Sammartino takes Pittsburgh territory over in 66; still billed as champion on an Altoona, PA paper as of 68/03.
Vacant on 83/04/03 after Tiger Mask is injured by
Dynamite Kid in a tag team match in 83/04/01; Dynamite Kid and Kuniaki Kobayashi
meet for the vacant title on 83/04/04 in Niigata, JPN but had no winner
Wins a triangular match defeating Davey Boy Smith
on 84/02/03 in Sappporo and The Cobra on 84/02/07; vacates in 84/11 when
Kid jumps to All Japan;
WWF takes over Georgia Championship Wrestling in 84/07, and Les Thornton,
who has been then billed as NWA World champion in Georgia,
wrestles as WWF champion in some WWF shows before title is forgotten.
New York, NY
Defeats Black Tiger.
The Cobra 
Vacates on 85/10/31 when New Japan and WWF end their working agreement;
Shiro Koshinaka defeats The Cobra on 86/02/06 in Tokyo to become the first IWGP champion.