Just finished my 77 this week.
This truck has stock 7" rally wheels with 275/60-15 tires.
Didn't want to go too low so I used the western chassis 3" drop spindles with stock springs for the front and for the rear I went the shackle and hanger route using the first hole in the shackles because the truck was already close to being level.
I think the previous owner had taken out the overload and one more leaf to level it because it doesn't have an overload leaf and it only has 6 total. I think the truck came with 8 from the factory.
For the record, removing those factory rivets was a pain in the a**!!
If I had it to do over, I would probably remove the bed to replace the hangers since bed removal is fairly easy.
Here are some pics
Before
After
Height differences between a stock spindle and the western chassis spindle.
