problems with locking hubs

[70 beast]

i posted the same question in my build but its kinda hiding so ill ask it here.

i recently swapped my 6 lug outers for 8 lug on my 71 jimmy's d44. the donor truck for the 8 lug was a 85 burb with a 10 bolt front with auto hubs. when i went to put the locking hubs on from the 6 lug outers they didn't seem to work.

is there something that i'm missing when a swap like this happens?

i researched new hubs in the attempts to find out and it said there's a spindle nut kit used when converting from auto hubs to manual.

i looked at the kit and i was wondering if i could use the spindle nuts and hardware from the 6 lug or is the new 8 lug spindle larger in diameter?

here is a link to the spindle nut kit on amazon
http://www.amazon.com/gp/product/B000182DZQ