I worked on my 70 Blazer NP205 a while ago and learned there were 2 size bolts used over the years. In my case I needed the narrower 7/16-14 thread bolt.
1969-70 used 7/16-14 x 2-3/4 bolt with 5/8 head
1971-72 used 9/16-12 x 2-3/4 bolt with 15/16 head
- the pic above from
jaros44sr is it.
- I may have one, shout if you want me to look, they usually go for around $50
-Jim