Re: 8” & 9” rear end? Poor man posi w/washers?
I do a lot of 8 and 9 inch Ford rears. If you are only using it for the drag strip, maybe, but I wouldn't do it. In the end, as that 1000 miles wears those shims, the teeth on the gears, and works all the spider wear surfaces, the metal is going somewhere, and that is in your oil.
Additionally, it is generating heat, also not good. In the end, there is no free ride. It's basically a tight diff, how loose it gets, depends how it wears. If it were me, I'd pull the center section, buy a traction lock or some other posi, or set it to factory specs.
70 Sportsroof, 427 FE/489 cid, TKO-600, 31 spline 4.10, A/C. modified Mass-flo EFI/reprogrammed A9L/CnC ported Victor.