... And here's why the right backspacing is important.
These are 295/50R15s on 15x10 Cragar S/Ss with 4.25" of backspacing.
While they look really cool just sitting there...
... they scrub the outer lip on just about everything - even with the 5-leaf spring pack, new shocks and bushings. I want a just little bit of boost in the back (the old school look works for me) so I'll be installing some factory-style 1-inch shackles, but the only way to make sure there are no rubs is to change the backspacing to get them tucked in a little tighter. Cragars (and most other rims) can be ordered with custom backspacing and/or offsets, so that's the way to go when it comes to stuffing the big rubber under there.
Some of the other guys have similar set-ups with better backspacing and report no issues. I think 5" of backspacing is about the least amount you want with 295s on 10" rims, but 5.25" or even 5.5" would be better. Another guy has 6.5" on his, and they fully tuck, but he said he had to modify the inner wheel houses to clear.
The fronts are 245/60R15s on 15x8s, BTW. No issues whatsoever.
Hope this "example of what not to do" helps someone avoid an expensive mistake in the future.