It's called afro engineering plane and simple!
I lowered my '85 Stepper this way back in '85 cuz droped spindels were not available yet!
I don't want you to think im bashing your truck but this is the worst way to lower any vehicle it's not safe by any means even though it's been that way for 20 years and you say you have had no problems.
When my truck was lowered this way i was wiping out LCA left & right if i went over a manhole cover that stuck up too much
and the ride quality was for $h!t it wouldnt' hold an alignment for more than 3 mo's. my front tires were allways cupping it would bottom out hard on a medium size bump/pot hole it was just BAD!
As far as spindels not allowing you to run a 10" rim im not shure what you mean by this i have 3" bell tech droped spindels on my '87 stepper and im running a 15x10" wheel with BFG 265-50-15 on 'em and i have on rubbing issues at all.
You will have a nice truck when it's finished and you have some bux tied up in it so why don't you just spend 3 or 400 bux on some quality spindels and do it right?
I shure would hate to see your finished ride get fuked up cuz you skimped on some lame lowering method instead of doing it right.
And today with all the way's to lower a truck the right way using quality kits i don't know why anyone would do it wrong or leave it like that theres just no reason too!
Click on my 87 stepper and look around and let me know what you think.