check the horse shoe bracket that the NSS switch tab goes into, i have had the same issue with my 70, replaced everything once , starter twice including battery cables work for a bit then not, i figured it out just by chance, i thought i had the NSS switch correct used alignment hole, start then wouldn't pushed the shifter all the way forward in park held it forward car started everytime. adjusted NSS switch bolt holes are slotted, currently no issues since then