8 3/4/stock axles/spool in a D100 - will it live long?

Put a '72 D100 together & the only third member I have laying around at the moment is a 3.90 with a spool. I'm going to daily the thing for a while & it may be a month or so before I get it swapped. What's the chances of snapping an axle? I've got the tires pumped up to 40 psi so they don't hook up as good & hopefully spin easier & I try to make all my turns wide & take the straightest paths through parking lots. Got a line on a 3.55 open but it's going to need gone through.

I've run a spool on street an I think It matters how big your tires are and how you drive. I would power up slitly on turns to help one tire slip

30 spline axles on a pickup should last forever,not enough weight back there.

I ran an 8 3/4 with stock axles and a spool with drag radials in the 11's for a couple years and at least 100 passes before swapping to a 35 spline spool and after market axles. The stock axles showed no signs of stress when I took them out. They are tough indeed.

I still have stock axles in my 63. I run 4.30's with a Detroit Locker and 30 x 9 radial slicks on the street. I have 7 years on them on the street with my 493 and about 20 track passes and last time I had the axles out they still looked fine. I plan to upgrade but so far they have held up better then I thought they would. Course my car is an auto car. Ron

Ran 4:30s in a 75 D100 440 4 speed , stock axles and spool for about 5 years(28k miles) , ran those old Mickey Thompson I tread tires on the street.

I daily drove a 360 Dakota for several years with a spool, 3.91 gears, and stock axles. No issues. The axles still looked perfect when the rear end came out of the truck.